Program Listings

Session Chair: Stefan Aschauer, PNSensor GmbH, Germany; Piero Giubilato, Padova University and INFN, Italy

We continue the study of micro channel plates (MCP) as the active element of a brand new shower maximum detector. We present below test beam results obtained with MCP-PMT and MCPs detecting directly secondary particles of an electromagnetic shower. The MCP efficiency to shower particles is close to 100%. The time and space resolution obtained for this new type of the SM detector is at the level of 1 mm and 25 ps.

A network of 16 Medipix-2 (MPX) silicon pixel devices was installed in the ATLAS detector cavern at CERN. It was designed to measure the composition and spectral characteristics of the radiation field in the ATLAS experiment and its surroundings. This study demonstrates that the MPX network can also be used as a self-sufficient luminosity monitoring system. The MPX detectors collect data independently of the ATLAS data-recording chain, and thus they provide independent measurements of the bunch-integrated ATLAS/LHC luminosity. In particular, the MPX detectors located close enough to the primary interaction point are used to perform van der Meer calibration scans with high precision. Results from the luminosity monitoring are presented for 2012 data taken at sqrt(s) = 8 TeV proton-proton collisions. The characteristics of the LHC luminosity reduction rate are studied and the effects of beam-beam (burn-off) and beam-gas (single bunch) interactions are evaluated. The systematic variations observed in the MPX luminosity measurements are below 0.3% for one minute intervals.

The Mu2e experiment at Fermilab proposes to search for coherent neutrinoless conversion of muons to electrons in the presence of a nucleus, an unambiguous signature of charge lepton flavor violation. An 8 GeV beam has about 31 million protons per pulse, of about 250 ns length and about 1695 ns between pulses. Any protons that hit the production target in between the pulses can lead to fake conversion electrons during the measurement period. We define the beam extinction as the ratio of the number of protons striking the production target between pulses to the number striking the target during the pulses. It has been established that an extinction of approximately 10-10 is required to reduce the backgrounds to an acceptable level. It is possible that changing conditions could result in degradation of the extinction on short time scales. It would therefore be desirable to measure the extinction of the beam coming out of the accelerator in a minute or less. Our technique is based on a telescope of four Cherenkov counters to register charged particles scattered off of a thin foil installed in the beam line. A beam time profile will be built by integrating over many bunches. The following Cherenkov radiators have been tested: melted quartz, UV transparent PMMA, and Cherenkov plastic with either Hamamatsu PMT R7056 or FEU-115M photodetectors. The R7056s were tested with cosmic rays at about 1.45 kV. The after pulses were observed at about a 20% level rate within a 1.8 µs window after the true pulses. In conjunction with x10 PM amplifier the high voltage was reduced to about 1 kV and the after pulses rate was at about 1-2%. To farther reduce voltage at the first stage we used custom made tampered voltage divider. To observe the PMT response at high frequencies, the R7056 was instrumented with a UV LED. At about 2 µA mean anode current and low illumination the PMT with factory tampered voltage divider was responded well up to 20 MHz frequency of pulses from generator to the LED .µ

The LASER calibration system of the ATLAS hadron calorimeter aims at monitoring the ~10000 PMTs of the Tile Calorimeter (TileCal). The LASER light injected in the PMTs is measured by sets of photodiodes at several stages of the optical path. The monitoring of the photodiodes is performed by a redundant internal calibration system using an LED, a radioactive source, and a charge injection system. The LASer Calibration Rod (LASCAR) electronics card is a masterpiece of the LASER calibration scheme. Housed in a VME crate, its main components include a charge ADC, a TTCRx, a HOLA part, an interface to control the LASER, and a charge injection system. The 13 bits ADC is a 2000pc full-scale converter that processes up to 16 signals stemming from 11 photodiodes, 2 PMTs, and 3 charge injection channels. Two gains are used (x1 and x4) to increase the dynamic range and avoid a saturation of the LASER signal for high intensities. The TTCRx chip (designed by CERN) retrieves LHC signals to synchronize the LASCAR card with the collider. The HOLA mezzanine (also designed by CERN) transmits LASER data fragments (e.g. digitized signal from the photodiodes) to the DAQ of ATLAS. The interface part is used during the pp collisions when the LASER is flashed in empty bunch-crossings. A time correction may then be performed, depending on the LASER intensity requested. The charge injection part aims at monitoring the linearity of the photodiode preamplifiers by injecting a 5V max signal with a 16-bits dynamics. All these features are managed with a field-programmable gate array (FPGA Cyclone V) and a microcontroler (Microchip pic32) equipped with an ethernet interface to the Detector Control System (DCS) of ATLAS.

The first technological SDHCAL prototype having been successfully tested, a new phase of R&D to validate completely the SDHCAL option for the International Linear Detector (ILD) project of the ILC has started with the conception and realization of a new prototype. The new one is intended to host few but large active layers of the future SDHCAL. The new active layers, made of GRPC with sizes larger than 2 m2 will be equipped with a new version of the electronic readout that was used in the technological SDHCAL prototype. The new version has additional features fulfilling the requirements of the future ILD detector. The new GRPC detectors are conceived to improve the homogeneity with a new gas distribution scheme. Finally the electron beam welding technique will be used to assemble the self-supporting mechanical structure of the new prototype. The progress realized will be presented and future steps will be discussed.

The Data Quality Monitoring (DQM) Software is a central tool in the CMS experiment. Its robustness and flexibility is critical for monitoring detector performance and providing fast and comprehensive feedback centrally for the experiment in real-time (Online DQM), after a full event processing with fine-grained analysis (Offline DQM), and as a validation tool to validate both the CMS software (CMSSW), calibration and alignment scenarios and extensive simulations. The entire DQM framework has undergone fundamental changes, and the first performance results of this newly updated system will be presented in the context of the first proton-proton collisions for CERN's Large Hadron Collider at a center of mass energy of 13 TeV. These results will encapsulate the performance of the CMS detector in the context of the upgraded DQM system that makes available more sophisticated methods for evaluating data quality, as well as a dedicated review of the technical challenges and improvements specific to the DQM framework itself. The plan to migrate the DQM GUI, the web base tool to deliver Data Quality information, to becoming a distributed system will also be presented.

The high-luminosity LHC (HL-LHC) upgrade is setting a new challenge for particle detector technologies. The increase in luminosity will produce a higher particle background with respect to present conditions. Performance and stability of detectors at LHC and future upgrade systems will remain the subject of extensive studies. The present contribution describes a joint project between CERN-EN and CERN-PH departments to design and build the new CERN GIF++ facility. GIF++ is a unique place where high energy charged particle beams are combined with a 14 TBq 137Cesium source. The intense gamma source produces a background field allowing to accumulate doses equivalent to HL-LHC experimental conditions in a reasonable time. The 100 m2 GIF++ irradiation bunker has two independent irradiation zones making it possible to test real size detectors, of up to several m2, as well as a broad range of smaller prototype detectors and electronic components. The photon flux of each irradiation zone can be tuned using a set of Lead filters with attenuation factors from zero to 50000. Flexible services and infrastructure including electronic racks, gas systems, radiation and environmental monitoring systems, and an ample preparation zone allow time effective installation of detectors. A dedicated control system provides the overview of the status of the facility and archives relevant information. Thanks to the collaboration between CERN and the users’ detector community, the latter providing detector specific infrastructures within the framework of the FP7 AIDA project, the new facility is now operational. A detailed program has been prepared to coordinate the R&D activities of about 15 detector groups from different LHC experiments during 2015.

The Pixel Luminosity Telescope (PLT) is one of the newest additions to the CMS detector for the LHC Run II data taking period. On each side of the CMS detector it consists of eight 3-layer telescopes based on silicon pixel detectors that are placed around the beam pipe viewing the interaction point at small angle. A fast 3-fold coincidence of the pixel planes in each telescope provides a bunch-by-bunch measurement of the relative luminosity. In addition to the physics program of CMS, this measurement is useful for accelerator diagnostics and optimization. Particle tracking information sampled at a kHz rate allows collision products to be distinguished from beam background, provides a self-alignment of the detectors, and provides for continuous in-time monitoring of the efficiency of each telescope plane. After calibration of the delivered luminosity in Van der Meer scans of the LHC beam, the PLT is expected to provide a high-precision measurement of the delivered luminosity of the LHC which is a crucial input for precision measurements of Higgs properties, determining particle production cross sections, and setting of mass limits on yet undiscovered particle production. An overview of the project, commissioning, and operational experience during this year’s LHC running are presented.

It is quite common practice to test detectors for high energy physics experiments using test beams, produced at various accelerator facilities. A key component of every test setup is a trigger system, which usually has to be provided by the team preparing the test. Therefore, a compact scintillating fiber detector has been built, with the aim of working as a position sensitive trigger device for testing Shashlyk-type modules of a new electromagnetic calorimeter (ECAL0), being built for the COMPASS experiment. A description of the construction of the detector is presented, followed by its performance evaluation using a low-intensity electron beam from the ELSA accelerator and electrons at the T10 test beam in CERN. The detector was adapted for use with acquisition system based on an 80 MSPS, 12-bit analog-to-digital converters. An effort has been made to develop a full Monte-Carlo model of the system, which includes simulation of particle interactions, detector optics, photomultiplier, signal acquisition electronics (both ADC and shaping, incl. noise simulation) and finally signal quantization, ADC non-linearity and its clock jitter.

The Mu2e experiment, designed to detect a hand full of events over a three year run, requires a cosmic ray veto to reject at least 99.99% of cosmic ray muons. This is done by the Cosmic Ray veto, consisting of four layers of scintillator, with WLS fiber and SiPM readout. The total area of coverage is 323 sq. m and requires 19k SiPMs. The CRV will also be subjected up to a dose of 5E9 neutrons per sq. cm (1MeV equivalent) over the experiments lifetime. As part of the campaign to identify SiPM devices that meet all out requirements of radiation hardness, efficiency and noise, we have undertaken a campaign to study radiation damage in a number of different devices from at least two vendors. We measure the response of the various SiPMs after exposing them to various doses of 200MeV protons. We have chosen 200MeV protons due to convenience, availability of excellent dosimetry (we are using a medical accelerator) and the fact that the bulk damage in Si from 200MeV protons is nearly equivalent to that of 1MeV neutrons. As the ability to detect single PE is a requirement for the proper operation of the CRV detector, we test a number of devices in the 10E9 to 10E10 n/sq. cm range and report results on dark current, dark rate, the dark PE spectrum and the relative photon detection efficiency. As we desire to measure surface mount SiPMs, while avoiding soldering or additional material being exposed, we developed an innovative method using a high resolution 3d-printed “waffle” pack that securely holds the SiPMs in a known position and allows us to move the tiny 1x1mm surface mount SiPMs from radiation to annealing to testing, without handling individual SiPMs and allowing reliable electrical contact for testing on conventional PCBs using anisotropic elastomer connectors. This makes it very simple to change devices, as surface mount devices vary greatly in dimensions and footprints. We simply print a different waffle pack to accommodate the differences.

In this study, the linear energy transfer (LET) spectrum of the hadrons along the path of a 62 MeV/amu Carbon ions’ beam, from the TANDEM accelerator at the INFN-LNS facility [1], has been measured in stacks of Intercast CR-39 detectors each of 1.5 mm thickness using the LET spectrometry technique described in M. Caresana et al. [2]. The measured spectra have been used to characterize the dose response of the track detector, for the development of a fast-neutron dosimeter based on this CR-39 detector [3], to high-LET heavy ions having a ß value (ratio between the speed of the particles and the speed of light) not greater than 0.1. The measured absorbed dose (mGy) and dose equivalent (mSv) has been compared to the FLUKA [4] particle transport code. The results show a good correlation between measured LET and dose from the Politrack reader and simulations results from FLUKA. The results confirms the analytical predictions where the Intercast CR-39 detector operates in its 100% efficiency range for the detection of heavy ions and the measurement of their LET for C ions with a ß value not greater than 0.1.

[1] Ciavola, G., Calabretta, L., Cuttone, G., Gammino, S., Raia, G., Rifuggiato, D., Rovelli, A. and Scuderi, V. (1993), "Recent improvements of the tandem facility at LNS", Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, A328. [2] M. Caresana et al., “Determination of LET in PADC detectors through the measurement of track parameters”, Nuclear Instruments and Methods in Physics Research, A 683, Pages 8-15, April 2012 [3] M. Caresana, M. Ferrarini, A. Parravicini., A. Sashala Naik, "Dose Measurements with CR-39 detectors at the CERF Reference Facility at CERN", Radiation Measurements, Volume 71, Pages 502-504, April 2014 [4] A. Ferrari, P.R. Sala, A. Fasso`, and J. Ranft, "FLUKA: a multi-particle transport code", CERN-2005-10 (2005), INFN/TC_05/11, SLAC-R-773

The conceptual design study of a hadron Future Circular Collider (FCC-hh) with a center-of-mass energy of the order of 100 TeV in a new tunnel of 80-100 km circumference assumes the determination of the basic requirements for its detectors. A superconducting solenoid magnet of 12 m diameter inner bore with the central magnetic flux density of 6 T is proposed for a FCC-hh experimental setup. The coil of 24.518 m long has seven 3.5 m long modules included into one cryostat. The steel yoke with a mass of 21 kt consists of two barrel layers of 0.5 m radial thickness, and 0.7 m thick nose disk, four 0.6 m thick end-cap disks, and three 0.8 m thick muon toroid disks each side. The outer diameter of the yoke is 17.7 m; the length without the forward muon toroids is 33 m. The air gaps between the end-cap disks provide the installation of the muon chambers up to the pseudorapidity of +-3.5. The conventional forward muon spectrometer provides the measuring of the muon momenta in the pseudorapidity region from +-2.7 to +-4.6. The magnet modeled with Cobham's program TOSCA. The total Ampere-turns in the superconducting solenoid coil are 127.25 MA-turns. The stored energy is 43.3 GJ. The axial force onto each end-cap is 480 MN. The stray field at the radius of 50 m off the coil axis is 14.1 mT and 5.4 mT at the radius of 100 m. All other parameters presented and discussed.

We realized a Micro-Waveguides Cherenkov (MWC) screen for Beam Profile Monitoring in order to measures the crossing particles via Cherenkov radiation emission in micrometric optical waveguides and a SiPMs (Silicon Photon Multipliers) based readout controlled by ARDUINO Ethernet for the CRYSBEAM experiment. A new generation of parasitic beam extraction of high energy particles from an accelerator is proposed in CRYSBEAM. Instead of massive magnetic kickers, bent thin crystals trapping particles within the crystal lattice planes are used. The R&D for the various components of such a system are carried out within this project and direct tests at CERN Super Proton Synchrotron to be performed prior to the final installation in the Large Hadron Collider are proposed. A new concept of particle accelerator operations will be finally set in place. The aim of the MWC screen is measure the deflected particles to achieve the profile of extracted beam with high intensity. The detector is made up of 20x20x2 mm3 fused silica screen with some micro-waveguides which are produced by means of an ultra-short laser micro-machining technique as for photonic devices used in quantum optics and quantum computing. The screen is a direct beam-imaging detector for a high radiation dose environment. Each micro-waveguide is read out by means of a SiPM optically coupled along the edge of screen. The readout electronics for SiPMs is a smart system of custom embedded boards called ArduSiPM prototype and based on an embedded board supplying bias voltage and analog readout channel made up of low-noise, high gain, fast recovery voltage amplifier and an ARDUINO based control electronics that allows temperature monitoring and gain calibration by Ethernet whit easy html-based user interface. The prototype of MWC screen was tested in April 2015 at the DAFNE Beam-Test Facility (LNF–Frascati (RM)) by fine-adjustable-multiplicity 500MeV electron’s beam. Different type of SiPMs was characterized.

At the Large Hadron Collider (LHC) experiments, most of silicon detectors use wire bonds to connect front-end chips and sensors to circuit boards for the data and service transmissions. These wire bonds are operated in strong magnetic field environments and if time varying currents pass through them with frequencies close to their mechanical resonance frequency, strong resonant oscillations may occur. Under certain conditions, this effect can lead to fatigue stress and eventually breakage of wire bonds. Systematic studies have been conducted to analyse the effects of resonance vibration on wire bonds. In particular, the case of the Insertable B-Layer (IBL) detector, the new innermost layer of the ATLAS Pixel Detector, has been reviewed. An experimental set-up has been built to simulate as much as possible the operation conditions of IBL wire bonds in the ATLAS magnetic field. The results provide useful information for the comprehension of the IBL wire bonds behavior. The dangerous resonance frequencies have been identified experimentally for different wire bond lengths. The resonance frequency amplitudes have been characterized in terms of several parameters, like wire length, wire orientation angle with respect to B-field and current amplitude. Several fatigue studies have been performed with simulations and laboratory tests. It has been demonstrated that in particular conditions, as for example with high currents, the wires can get irreparably damaged after few oscillation cycles and they can break. Two types of wire bond protections have been considered: the classical encapsulation of the wire feet and the coating of the whole wire. The results reveal that these methods minimize the oscillation amplitude reducing the possibility of damaging or breaking the wire bonds. For the IBL detector a Fixed Frequency Trigger Veto has been implemented for excluding the potentially dangerous frequencies identified in these studies.

The LEETECH (Low Energy Electrons TECHnique) versatile platform has been constructed at the photoinjector PHIL at LAL, Orsay. Samples of low-energy electrons of variable multiplicity and energy are delivered for development of various detector technologies as well as for precision studies of electron energy losses. LEETECH delivered first electron samples at the end of 2014. We report characterisation of the LEETECH spectrometer and first results on the detectors R&D using LEETECH. The approach of the dE/dx studies using Micromegas InGrid detector for low-energy electrons is presented based on full simulation and first experimental results.

Abstract: Novel calorimeter sensors for electron, photon, ion and hadron energy measurement based on Secondary Emission(SE) directly from dynodes to measure ionization is described, using sheet-like dynodes as the active detection and amplification medium. The shower particles in an SE calorimeter cause direct secondary emission from dynode arrays comprising the sampling and/or total absorbing medium. Each secondary electron generated by the shower particles is amplified by the dynode stack and is thus similar to a photoelectron. As comparison with scintillator/PMT calorimeters, large amounts of light are created, but converted to photoelectrons low efficiency. In a secondary emission calorimeter, fewer secondary electrons are created, but most of them are captured and amplified. Data is presented on prototype secondary emission module tests using PMT with disabled photocathodes, and detailed GEANT4 Monte Carlo simulations are compared with test data. For a monotonous 5 µm thick Cu dynode stack as the sensor-absorber-amplifier, the tuned MC indicates potential resolutions with a stochastic term = 1%/E(GeV), and possibly even applicable to nuclear spectroscopy. This sensor can be made radiation hard at GigaRad levels as shown by PMT dynodes, and secondary emission beam monitors used at accelerators. Mesh-like dynodes are easily transversely segmentable at the mm scale. In a calorimeter, energy signal rise-times and integration times are significantly shorter than scintillation/PMT calorimeters. The sensor fabrication is low cost compared with PMT since the vacuum needed is less by x100, no photocathode is needed and thereby the assembly can be taken to high temperature for cleaning and brazing. Applications are mainly in the energy and intensity frontiers. Possible coatings for high performance include synthetic diamond dynodes, and neutron-converting dynodes.

The Monitored Drift Tube (MDT) chambers of the ATLAS muon spectrometer demonstrated that they provide very precise and robust tracking over large areas. Goals of ATLAS muon detector upgrades are to increase the acceptance for precision muon momentum measurement and triggering and to improve the rate capability of the muon chambers in the high-background regions when the LHC luminosity increases. Small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages with the MDTs, but have an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, reducing cost and construction time considerably and improving the the sense wire positioning accuracy to better than ten microns. The construction of twelve chambers for the feet regions of the ATLAS detector is currently ongoing with the goal to install them in the winter shutdown 2016/17 of the LHC. Design and construction of the new sMDT chambers for ATLAS will be discussed as well as measurements of their precision and performance.

With the restart of the LHC in 2015, the growth of the CMS conditions dataset will continue, therefore the need of consistent and highly available access to the conditions makes a great cause to revisit different aspects of the current data storage solutions. We present a study of alternative data storage backends for the CMS Conditions Databases, evaluating some of the most popular NoSQL databases to support a key-value representation of the CMS conditions. In addition to the baseline performance comparison between a document store, a column-oriented, and a plain key-value store, the access layer for these databases in the CMS software was developed, in order to provide transparent support for these alternative data stores in the CMS context. Necessary changes in the software infrastructure, and in the modelling approaches are also discussed in this paper. We also discuss the validation phase, which plays a key role in the optimization of the different solutions with fine-tuning critical performance factors.

The Machine Protection System (MPS) for the Fermilab Accelerator Science and Technology Facility (FAST) has been implemented and tested. The system receives signals from several subsystems and devices which conveys the relevant status needed to the safely operate the accelerator. Logic decisions are made based on these inputs and some predefined user settings which in turn controls the gate signal to the laser of the photo injector. The inputs of the system have a wide variety of signal types, encoding methods and urgencies for which the system is designed to accommodate. The MPS receives fast shutdown (FSD) signals generated by the beam loss system and inhibits the beam or reduces the beam intensity within a macro-pulse when the beam losses at several places along the accelerator beam line are higher than acceptable values. TTL or relay contact signals from the vacuum system, toroids, magnet systems etc., are chosen with polarities that ensure safe operation of the accelerator from unintended events such as cable disconnection in the harsh industrial environment of the experimental hall. A RS422 serial communication scheme is used to interface the operation permit generator module and a large number of movable devices each reporting multi-bit status. The system also supports operations at user defined lower beam levels for system commissioning. The machine protection system is implemented with two commercially available off-the-shelf VMEbus based modules with on board FPGA devices. The system is monitored and controlled via the VMEbus by a single board CPU.

Radiation-hard detectors are needed for the High-Luminosity upgrade for the ATLAS experiment at the Large Hadron Collider at CERN. 3D silicon devices are a technology which may be able to provide the required resolution and durability when exposed to ionising radiation. 3D sensors have electrodes processed inside the silicon bulk rather than being implanted on its surface. This paper will present a comparison of the performances of 3D and planar silicon sensors, both connected to pixel-based TimePix readout chips. The 3D detector was found to have less charge sharing and to operate at a lower bias voltage than the planar detector, due to the smaller electrode separation in the latter.

One of the possible methods of studying yrast and yrare states of extremely neutron deficient nuclei is by using heavy-ion induced fusion-evaporation reactions. In such experiments, the nuclei of interest are produced with very low cross sections, therefore clean reaction channel selection is essential. State-of-the-art gamma spectrometers coupled to high performing ancillary detectors are the key instruments to study the nuclear structure of this neutron deficient N~Z nuclei. The most exotic (and the most interesting) reaction channels are almost always associated with the emission of neutrons, two or more. Currently, a new neutron multiplicity filter named NEDA (NEutron Detector Array) is being constructed for this purpose. NEDA will operate with germanium arrays (AGATA, GALILEO, EXOGAM) on both intense stable and radioactive ion beams. This will enable to investigate the structure of exotic neutron-deficient nuclei, which were not experimentally achievable so far. The efficiencies of clean identification of 2n and 3n reaction channels are expected to be a few times higher for NEDA with respect to existing arrays. The findings from the R&D phase and the status of the NEDA project will be presented. This involves results of Geant4 simulations on optimal single detector size, scintillator materials and geometry of the whole array. The results of measurements with the prototype detectors will be presented. Comparison between analog and digital procedures for the neutron-gamma discrimination and timing will also be discussed.

Background and objectives: Very intense pulses of protons and ions can be produced in laser-plasma interactions at ultra-high energy densities. In a Thomson parabola spectrometer (TPS) the accelerated particles are separated by their mass, charge, and momentum. We present the design of a TPS for the spectral characterisation of laser-accelerated protons and carbon ions which will be implemented in a table-top laser setup which is currently under preparation. Method: First estimates of the magnetic and electric fields as well as the particle flight paths necessary for the clear separation of particle momenta have been obtained from well-known equations. We have designed a pair of permanent magnets with a C-shaped yoke to achieve a field of the order of 0.6~T. An exact field map has been obtained from simulations with COMSOL Multiphysics. The same software has been used to simulate the electric field between charged copper plates and the depletion of particles in the entire detector system. Results: The magnetic field is reasonably uniform (up to 10\% deviation) in a large volume between the pole shoes. Our versatile setup allows for adjusting the desired energy range by variation of the path length and field gradient of the electric field, and by variation of the position of the detector plane. In the case of protons the low-energy interval ranges from 100 to 1000~keV, and the high-energy interval, from 1 to 10~MeV. Carbon ions can be separated by charge and momentum in both configurations.

The PHENIX Collaboration at RHIC is in the early stages of a major upgrade, with the goal of performing comprehensive measurements of jets in relativistic heavy ion collisions. The upgrade will provide enhanced physics capabilities for studying nucleon-nucleus and polarized proton collisions, and will serve as the baseline detector for a detailed study of electron-nucleus collisions at the envisioned future Electron Ion Collider (eRHIC) at Brookhaven. The upgraded detector, code-named "sPHENIX", will be based around the former BaBar solenoid magnet. It will include two new large calorimeters, a tungsten-scintillator electromagnetic calorimeter, and the first-ever hadron calorimeter at the relativistic Heavy Ion Collider. The inner volume will house a tracking system. Both a silicon tracker-based solution and an alternative setup using a central TPC are currently under study. This paper will discuss the required physics capabilities, granularities, and resolution parameters. We will show the main components of the new sPHENIX apparatus, and present design studies and the results of ongoing tests. We will discuss what kind of measurements the enhanced physics capabilities, especially for measuring jets, will enable, and outline envisioned evolution paths towards a future eRHIC detector.

The Hadron Forward Calorimeter of CMS completed the Long Shutdown 1 part of the Phase I upgrade. Approximately 1800 photomultiplier tubes were replaced with thinner window, higher quantum efficiency, four-anode photomultiplier tubes. The new photomultiplier tubes will provide better light detection performance, a significantly reduced background and unique handles to recover the signal in the presence of background. The upgrade is also associated with new cabling and channel segmentation options. This report will describe the upgrade and the nature of the essential upgrade elements with supporting test results.

The DEPFET collaboration develops highly granular, ultra-transparent active pixel detectors for high-performance vertex reconstruction at the Belle II experiment, KEK, Japan. The key features of the sensors have been proven: integration of the first amplification stage into the sensor, very low sensor thickness, high signal-to-noise ratio, non-destructive pulse-height readout, and the connection to readout ASICs with sufficient speed. A complete detector concept is being developed, including solutions for mechanical support, cooling and services. During beam injection, the sensors will be flooded with meaningless particle hits which have to be ignored. To do so, the sensors will be switched to the so-called ``gated mode''. This is a kind of electronic shutter in which the signals of previous particles are preserved, and the signals of upcoming background particles are cleared right away. After a brief introduction to the Belle II experiment, the Pixel Detector PXD and the DEPFET sensor concept, this contribution will focus on the first measurement results of the gated mode operation. It will discuss the underlying principle, the laboratory setup, and the results of laser tests showing that the DEPFET sensor can indeed be blinded against new signals while preserving the signal state before entering the gated mode. This is not a simple proof of concept, because we use the (close to) final readout ASICs and apply procedures as similar to the real experiment as possible. The aim is to demonstrate that the DEPFET sensor indeed is capable of dealing with the injection noise of the new SuperKEKB collider.

The electromagnetic calorimeter (EMC) of the PANDA detector at the future FAIR facility is composed of two endcaps and a barrel covering the major part of the solid angle consisting of more than 11.300 tapered PbWO4 crystals. The individual scintillator modules are readout via two large area avalanche photo diodes. The signal processing is performed with a custom made ASIC-preamplifier providing a large dynamic range, low noise and reduced power consumption since the calorimeter will be operated at a temperature of -25oC. In order to optimize the mechanical design, to accomplish the limited space and to reach an optimum overall performance in particular with respect to the energy resolution a prototype (PROTO120) has been constructed containing 120 detector elements, a small part of one of the in total 16 slices housing 710 detector modules each. The paper will present based on a series of in-beam tests with mono-energetic photons up to 800 MeV at the tagged photon facility of MAMI at Mainz the finally achievable performance to be expected for the calorimeter. Energy, position and time resolution will be deduced for the entire energy range focusing in particular onto energies below 100 MeV which are most sensitive to the contribution of electronic noise. The strong tapering the crystals leads to a non-uniformity in light collection, which causes a smearing of the response, resulting in a reduction of the energy resolution in particular at higher energies. Therefore, a sub-matrix of crystals has been modified by depolishing one lateral crystal side to a roughness of 0.3 µm, which decreases significantly the non uniformity but reduces the overall light yield. The present study will compare the response with a similar matrix of polished crystals and discuss the applicability in case of the PANDA requirements.

The Fermilab Test Beam Facility is a world-class facility devoted to particle detector R&D and has recently undergone extensive upgrades. In the past 2 years, a second beamline has been added, with cryogenic support for liquid Argon detectors. Both beamlines can deliver a variety of particle types and momenta. The MTest primary beamline consists of a beam of high energy protons (with 120 GeV/c momentum) at moderate intensities (~1-300 kHz). This beam can also be targeted to create secondary particle beams of momenta down to 1 GeV/c, consisting of pions, muons, and electrons. The MCenter beamline includes the same range of particles and momenta from the secondary beamline and includes a tertiary beamline with particle momentum down to 200 MeV/c. Analysis of the beam in both beamlines has begun and we will present event rate, trigger purity, momentum spectrum analysis and time of flight performance. We also created a high rate tracking area and cosmic teststand. Updates to the facility data acquisition system and tracking capabilities will also be shown. These additions makes the Fermilab Test Beam Facility one of the most versatile test beamlines in the world and capable of supporting R&D initiatives from both industry and HEP users.

Cerenkov Compensated/Dual Readout Calorimeters constructed with alternating scintillator tiles and low refractive index Cerenkov tiles (including Cerenkov Tiles added to Particle Flow Calorimetry) are studied in Monte Carlo. We study adding Cerenkov tiles to Shashlik calorimeters, Shashlik-like e-m calorimeters with Cerenkov (heavy rad-hard glasses) and Scintillator tiles but without absorber, and hadron calorimeters with scintillator and Cerenkov tiles. The Cerenkov tiles are varied between n=1.1 (Silca aerogels) thru n=1.9 (some rad-hard heavy glasses). We show that it is easier to compensate an all active e-m calorimeter using scintillating crystals by introducing Cerenkov tiles, and that the tile geometry is superior to the parallel fiber technique for dual readout both in practical collider calorimeters and in general principles of compensation. We then make estimates of the improvements possible to particle flow by adding Cerenkov-like compensation. Improved calorimetric technologies are essential in energy frontier experiments at future machines for improving jet energy and angle resolution; isolation and ID of electrons & muons. Particle Flow Calorimetry and Dual Readout are developing calorimeter technologies capable of sufficient energy resolution, segmentation, and rate.

The Muon g-2 Experiment, E989 at Fermilab, will measure the muon anomalous magnetic moment, a=(g-2)/2 to unprecedented precision: the goal is 0.14 parts per million (ppm). It is expected to start data taking in 2017. To achieve a statistical uncertainty of 0.1 ppm, the total dataset must contain more than 1.8 x 10¹¹ detected positrons with energy greater than 1.8 GeV. The new experiment will require upgrades of detectors, electronics and data acquisition equipment to handle the much higher data rate. In particular, it will require a continuous monitoring and state-of-art calibration of the detectors, whose response may vary on both the millisecond and the several hour timescales. This monitoring will be achieved by sending trains of calibrated laser pulses simultaneously to all detectors. The main characteristics of the Laser Control system are presented.

Current and future high energy physics particle colliders are capable to provide instantaneous luminosities of 10³⁴ cm^-2 s^-1 and above. The high center of mass energy, the large number of simultaneous collision of beam particles in the experiments and the very high repetition rates of the collision events pose huge challenges. They result in extremely high particle fluxes, causing very high occupancies in the particle physics detectors operating at these machines. To reconstruct the physics events, the detectors have to make as much information as possible available on the final state particles. We briefly discuss how timing information with a precision of around 10 ps and below can aid the reconstruction of the physics events under such challenging conditions. We discuss different detector concepts which can provide time measurements for charged particles and photons with a precision in the range of a few 10 ps. We present in detail updated measurements utilizing a LYSO based calorimeter prototype. With an improved understanding of the signal creation, light propagation and detection characteristics we achieve a precision of 40 ps for electrons with energies of 30 GeV. Further we present beam test measurements with a multichannel plate based detectors and studies using silicon detectors. We discuss possible implementations based on these different technologies in a large scale particle physics detector.

PANDA is a key experiment of the future FAIR facility and the Micro Vertex Detector (MVD) is the innermost part of its tracking system, designed to identify primary and secondary vertices. It will be composed of four concentric barrels and six forward disks, instrumented with silicon hybrid pixel detectors and double-sided microstrip detectors. The layout of the two strip barrels of the PANDA MVD foresees square and rectangular sensors, arranged in linear staves. The compact layout of the detector poses significant challenges on its integration. The staves consist of a carbon fiber support structure, which will ensure the precise positioning of the sensitive elements while keeping the material budget low. The sensors are glued directly on the stave; the readout chips are placed next to the sensors supported by a flexible multilayer bus. The carbon fiber staves feature an embedded cooling system, consisting of a nickel- cobalt alloy pipe surrounded by a block of carbon foam, which is inserted in the stave during manufacturing. The steps required for the manufacturing of the staves have been optimized through the fabrication of several prototypes. A complete stave has been used to perform a test of the cooling system, using resistors to simulate the heat dissipation of the chips. The multilayer bus will be used to connect the readout chips to the sensor, as well as to provide the interconnection between the various chips and to distribute the power supply to the chips and to the sensors. In a first prototype run, the fanout structure was implemented on standalone pitch adaptors as well as in one-chip carrier boards, which have been assembled and tested. A more complex layout, hosting six readout chips with a geometry closer to the final one, has been designed and is currently under production. In this contribution, the status of the design of the barrel staves and the studies performed on the prototypes of the various components will be presented.

To extend the physics reach of the LHC, upgrades to the accelerator are planned that will increase the peak luminosity by a factor 5 to 10. To cope with the elevated occupancy and radiation damage, the ATLAS experiment plans to introduce an all-silicon inner tracker with the HL-LHC upgrade. With silicon, the occupancy can be adjusted by using the appropriate unit size (pixel, strip or short strip sensors).

To investigate the suitability of pixel sensors using the proven planar technology for the upgraded tracker, the ATLAS Planar Pixel Sensor R&D Project was established comprising 19 institutes and more than 90 scientists. Main areas of research are the performance assessment and improvement of planar pixel sensors at HL-LHC fluences, establishment of reliable device simulations for irradiated sensors, the exploration of possibilities for cost reduction to enable the instrumentation of large areas, and the achievement of slim or active edges to provide low geometric inefficiencies.

The presentation will give an overview of the accomplishments of the R&D project. Among these are results obtained with different pixel sensors irradiated up to HL-LHC fluences with thicknesses down to 50 micron and with different slim and active edge approachess. In addition, sensors also for the outer layers have been prototyped and characterization results will be shown including beam test data.

In summary, a comprehensive overview of the current state-of-the-art in radiation-hard planar pixel sensor development for future HL-LHC applications will be given with emphasis on performance of prototypes after irradiation to realistic fluences.

The phase 1 upgrade of the CMS pixel detector will replace the existing pixel detector at the end of 2016 in an extended technical stop. The phase 1 upgrade includes four barrel layers and three forward disks, providing robust tracking and vertexing for LHC luminosities up to 2.5 x 10^34 cm-2 s-1 prior to the HL-LHC era. The upgrade incorporates new readout chips and front-end electronics for higher data rates, DC-DC powering, and dual-phase CO2 cooling to achieve performance exceeding that of the present detector with a lower material budget. The design of the forward detector is presented along with present status of mechanical construction, module assembly, and module qualification. The procedures for module testing and quality assurance are described in some detail.

The CALICE Collaboration developed the Digital Hadron Calorimeter in the context of studies of future collider detectors that are optimized for the application of Particle Flow Algorithms. The Digital Hadron Calorimeter uses Resistive Plate Chambers as active media and has a 1-bit resolution (digital) readout of 1 x 1 cm² pads. As part of the broad test beam program, the calorimeter was also tested in a setup with no absorber plates between the active layers. Electromagnetic calorimeters are typically dense and compact, in order to contain the entire shower in the smallest possible volume with the best energy resolution. In such calorimeters the topological details about the electromagnetic interactions are not detectable. With the minimal-absorber setup of the Digital Hadron Calorimeter, electromagnetic showers were measured with unprecedented topological details. Here we describe the setup and the unique dataset collected at Fermilab, which contains electromagnetic showers extending into 1 m³ of detector volume. We report on basic calorimetric measurements, as well as on detailed measurements of electromagnetic shower shapes. The results are compared to Monte Carlo simulations based on GEANT4.

The Mu2e experiment requires a very high efficiency (99.99%) Cosmic Ray Veto to reject events that mimic a muon to electron conversion. The CRV covers an area of 323 sq. m and consists of 4 layers of extruded scintillator with WLS fiber readout and using SiPMs as photodetectors. To meet the strict requirements on the efficiency of the detector in the face of intense background radiation, while maintaining a low cost, we designed new front end electronics that is simple, relatively inexpensive in small quantities and has very good performance. Using a commercial 12bit waveform digitizer operating at 80MSPS to capture the signals from every SiPM in the system and having sufficient memory on board to capture the entire waveform for the time of interest, if necessary allows us to extract maximum information from the signal to be able to reject most of the background while maintaining excellent efficiency and acceptable deadtime. There are approximately 300 front end boards in the CRV system, each with 64 channels. The connection to the SiPMs is made using very inexpensive HDMI cables, one cable to four SiPMs. The analog performance of the board allows the gain of the amplifier to be adjusted for every SiPM. The voltae is generated on board and can be adjusted over an 8V san for each SiPM individually. A current measurement circuit is able to measure the bias current with a resolution of better than 100ps. The board carries 1GB of LPDDR RAM. Interaction with the board is over ethernet or USB.

We realized a Nuclear Interaction Detector (NID) system based on thin plastic BC-408 scintillator and MPPC readout , controlled via Ethernet, for the H8 telescope of the UA9 experiment. The UA9 experiment was installed in the CERN-SPS in the 2009 with the aim of directly testing the crystal assisted collimation as an alternative for both protons and lead ion beam collimation in the LHC. UA9’s final goal is to demonstrate that crystal based collimation has a higher cleaning efficiency than traditional scheme. Measurements of suitable crystals are being carried out in the SPS ring as well as in a fixed target experiment in the CERN North experimental area The aim of the NID is the precise measurements of nuclear interactions probability between crystal and particles in the various channeling regimes (channeling, volume reflection etc.) The NID made up of a small scintillator fiber as trigger of system and 2 small scintillator (5x15x10 mm3 of BC-408) as nuclear interaction counters. Optical readout made up of a pair of Hamamatsu S10362-33 Multi Pixel-Photon Counters (MPPC) per scintillator directly coupled with it and put in coincidence. The MPPCs are driven by an electronics system called ArduSiPM prototype (the first version of the system) made up of an embed board supplying bias voltage and analog readout channel for every MPPC and of an ARDUINO based control electronics which allows temperature monitoring and gain calibration by Ethernet whit easy html-based user interface. The NID system is installed on H8 beam line at CERN North experimental area and is measuring the nuclear interaction events on crystal characterization.

Compton imaging is a very useful for gamma-ray and high enegy X-ray imaging in the medical and environmental applications, but the full Compton cones in the reconstruction could cause the loss of total sensitivity and artifact. The recoiled electron provides the additional information to the incoming gamma rays for making partial Compton cones. SOI (Silicon-on-Insulator) technology is a integrated technology of sensor and circuit in a monolithic way. The event driven SOI sensor (XRPIX) has been developed for X-ray imaging which generates the trigger above the predetermined threshold . XRPIX has the pixel size of 30µm and the thickness of 250 µm/500µm silicon layer in CZ/FZ process. For the advanced Compton imaging a prototype of Compton camera using SOI sensor and GAGG/MPPC array as a scatter and an absorber. The pattern readout and coincidence detection is implemented in the control/DAQ FPGA for the high-speed readout. The pattern of Compton electrons is detected and the first image is reconstructed using SOI/GAGG-MPPC Compton camera.

The usual process used to fabricate planar diode arrays on high-resistivity silicon was first outlined by Joseph Kemmer [1]. It is based on the use of a rather thick thermally grown silicon dioxide layer between the ion implants which form the diode elements to electrically isolate the diodes from each other. The full process as implemented in our laboratory uses a total of 5 masks for the basic structure, interleaved with several deposition and etching steps. Much of this labor can be avoided if the isolation is provided not by field oxide, but by etching trenches into the silicon which define the diode boundaries. Additionally, this technique can also effectively reduce the inter-pixel capactiance by a factor related to the dielectric constant of silicon. Detailed TCAD silimulation has shown clear reduction in the inter-pixel capacitance. This technique has been demonstrated to be effective for realizing detectors made of High-Purity germanium (HPGe) or lithium-diffused silicon (Si(Li)). We have used this approach to fabricate 384 pixel array detector in a conventional high-resistivity silicon wafer. Using the metal layer as a mask different trench thickness were etched in Si using inductively coupled deep reactive ion etching. Details of detector characterization and capacitance measurements will be presented.

Many elementary-particle and nuclear physics experiments are performed at temperatures below 200 Kelvins. Examples include the Enriched Xenon Observatory (EXO), Background Imaging of Cosmic Extragalactic Polarization (BICEP), and the Cryogenic Dark Mark Search (CDMS) project. As channels counts and sensor densities increase there is a growing need for flip-chip bonding as a method for forming interconnections between the silicon integrated circuit and sensor chip. Studies have been performed to determine the robustness of the hybrid chip created by flip-chip bonding under thermal cycling to temperatures below 1 Kelvin. Using Indium as the bump material provides a soft interface with modest ability to conform to stresses in a partially elastic manner. Flexible substrates are widely used in the construction of photon science and particle physics detectors. The ability to flip-chip bond flexible substrates to rigid parts or other flexible substrates can be enabling and is not a standard process. Procedures are being developed to fabricate conducting traces on flexible substrates with line-space features as small as 5 microns. Flip-chip attachment to compliant films composed of a variety of materials will be reported upon.

The space radiation induced displacement damage effects on the performance of the Silicon Drift Detector (SDD) based X-ray spectrometer has been studied using X-ray (Fe-55) and gamma ray (Co-60) radiations. The spectroscopic performance of the SDD based spectrometer degrades due to radiation damage during the transit and in-orbit operations. Silicon detectors are sensitive to displacement damage which is due to the non ionizing energy loss of the incident radiation. The displacement damage increases the leakage current of the SDD and hence the energy resolution. The X-ray irradiation is to quantify the X-ray fluence level up to which the SDD provides stable energy resolution. After X-ray irradiation tests, it is observed that there is no change in the leakage current and the energy resolution for dose up to 64 krad. The gamma ray irradiation test is to quantify the space radiation damage effects on the SDD and shown that the energy resolution degrades from ~160 eV at 5.9 keV to ~210 eV for the detector operating temperature of ~-40oC for the gamma ray dose of ~10 Krad. It is observed that the increase in the leakage current due to displacement damage is ~0.15 pA and its contribution to the degradation in the energy resolution is insignificant. The degradation in the energy resolution is attributed to the radiation damage of the electronic components inside the SDD module and meets the Chandrayaan-2 requirement of < 250 eV for the mission life of 2 years.

The Canberra SAGe Well detector is a large volume germanium detector in an inverted coaxial geometry with a single small anode on the back face. The small anode has a low capacitance which results in low electronic noise levels and allows excellent energy resolution to be achieved (0.75 keV FWHM @ 122 keV). Secondary effects of the small anode include extremely long charge drift times (>1 µs) and a signal where most of the induced charge is produced in the last short fraction of the risetime. This unusual pulse shape aids in the identification of multiple interactions but also creates unique challenges for timing measurements. Three SAGe Well detectors have been studied at the University of Liverpool. The performance of these detectors for environmental measurements has been studied and the improved energy resolution has been found to provide increased sensitivity in 210Pb assay. For one detector a full signal shape characterisation has been performed using a coincidence scanning system and the results are currently being used to optimise an electric field simulation of the detector. Once simulations are complete and validated the results will be used to optimise risetime based background suppression and timing algorithms. We will describe the detector characterisation methods and present the analysed data. An update will be provided on algorithm development.

In order to fulfil the need of cheap and high-resolution radiation beam monitors we exploited the possibility of using commercial CMOS image sensors as X-rays and low-intensity particle beam monitors. CMOS sensors nowadays offer a wide range of resolutions with excellent spectral and chromatic responses as well as generally low cost. We have now selected a novel CMOS sensor that is provided in a naked packaging. This opens the way to improved performance in X-ray sensing even at lower energies, where the small depleted volume typical of a CMOS sensor provides the best efficiency. The paper will focus on the description of the architecture of the sensor system and on the results of the experimental qualification of the sensor cell and of the imaging system as X-ray imager and beam monitor.

This work is focused on Metal-Oxide-Semiconductor (MOS) injector devices for the calibration of the semiconductor detectors? response by means of the point injection of electron charge. The amount of injected charge depends on several parameters such as pulse amplitude, width and repetition rate, injector DC bias voltage and geometrical properties. We present a multi-parameter experimental study aimed at clarifying the MOS injector physical mechanism and the inter-relationships among the relevant parameters. MOS injectors of different geometries have been inserted in a multi-linear silicon drift detector prototype for evaluation purpose. The set of obtained experimental results allows the development of a suitable model for better understanding and for the optimization of the injector design.

A novel silicon strip detector for the beam monitoring at the Micro-beam Radiation Therapy (MRT) is presented. This treatment is one of the most recently developed. It relies on the irradiation of tumors using an array of parallel micro-beams only a few tens of micrometers wide and with a pitch that ranges between 100 and 400 µm. The filtered white beam X-ray energies span between 50 and 600 keV and deliver extremely high radiation dose rates of ~20 kGy/s (~2 MRad/s). The requirements for the silicon dosimeter are: small beam perturbation, high spatial resolution and long lifetime. To achieve this, a silicon strip detector was specially designed. In order to avoid beam perturbation and readout electronics saturation, the devices are thinned down to ~10µm using an anisotropic TMAH etching. Radiation hardness is assured by limiting the surface radiation damage with the use of a combination of p-stop/p-spray implantation. In this study electrical and functional characterizations will be presented, comparing to numerical simulations where possible. The fabricated devices were tested at the ESRF at the ID17 and ID21 beam lines to demonstrate their beam monitoring capabilities. Good performances were found in different operating condition, despite the non-optimized measurement setup at ID17. Additional confirmation of the correct sensor operation was obtained from 2D signal efficiency scans performed with a sub-micron X-ray beam at ID21. The performed tests suggested some sensor layout and measurement setup modifications that are here discussed as well.

The development of an innovative position sensitive pixelated sensor with low material budget to measure with high precision the coordinates of the ionizing particles is proposed. The silicon avalanche pixel sensors (APiX) is based on the 3D technology, vertical integration of avalanche pixels connected in pairs and operated in coincidence in fully digital mode and with the processing electronics embedded on the chip. The APiX sensor addresses the need to minimize the material budget and related multiple scattering effects in tracking systems as vertex detector requiring a high spatial resolution in the presence of a large occupancy. The expected operation of the new sensor features: low noise, low power consumption and suitable radiation tolerance. The APiX device provides on-chip digital information on the position of the coordinate of the impinging charged particle and can be seen as the building block of a modular system of pixelated arrays, implementing a sparsified readout. The technological challenges are the 3D integration of the device under CMOS processes and integration of processing electronics. In order to demonstrate experimentally the validity of the APiX structure detection principle, a very preliminary prototype of a single avalanche pixel structure was assembled starting from a pair of SiPM sensors. Results of the response of the prototype tested at the CERN SPS test beam area will be shown.

We report on the measurements of the time resolution of Ultra-Fast Silicon Detectors (UFSD). UFSD are silicon sensors based on the Low-Gain Avalanche Diodes (LGAD) design and, due to internal gain, exhibit a signal which is a factor of ~ 10 or more larger than standard silicon detectors. The internal gain allows obtaining fast and large signals, ideal for time applications. The time resolution was measured both with 1064nm laser signals and in beam tests with electrons and pions. The pulse shapes are recorded in a digital scope and analyzed off-line. Here we report the dependence of the time resolution on the “slew-rate” dV/dt which is influenced by the detector capacity and the detector thickness, in addition to the internal gain. Finally we compare the results with the prediction of the simulation program Weightfield 2.

Performing X-ray polarimetry of astrophysical sources is a topic of growing interest, with only a few flying experiments dedicated to it so far. For soft X-rays sources detection from 1keV to few tens of keV, the best technique certainly consists in using the photoelectric effect, which is the dominant phenomenon at those energies in gaseous detectors. One of the main issues of such detectors to consider their reliable use in space is that gaseous detectors and associated front-end electronics are sensitive to sparks caused by cosmic rays. To overcome this limitation, we investigate the opportunity of building a new spectro-polarimeter with outer and contactless radiation hard readout electronics, placed outside the gas chamber. The readout electronics in question inherits from Caliste-HD, a fine pitch 3D detector module initially designed for semi-conductor applications. In this paper, we present the different part of our experimental setup prior to show up recent results obtained by illuminating our prototype with a 55-Fe source. On top of presenting several interesting curves for the detector's parameters, we also present the first spectrum of a soft X-ray gaseous detector with outer and contactless electronics, making a step forward in the field of soft X-rays spectro-polarimeter.

In the framework of the Pierre Auger Observatory upgrade, which foresees the installation of scintillator-based surface detectors placed above the water-Cherenkov tanks, we studied the light yield and the effect of temperature cycling for different extruded scintillators/optical fibers configurations. In this paper we will report on the light yield of extruded scintillators read out with wavelength shifting optical fibers, optically coupled to a PMT. We tested many different geometries, different fibers qualities and diameters and different scintillators providers. Then, for a selected number of configurations, we tested the effect of temperature variations on the detector response, in a climatic chamber. In order to reproduce the thermic excursion that will affect the detectors installed in the field in Argentina (between -5°C to +40°C), we studied the scintillator response in the temperature range from -20°C to +70°C. We performed as well many temperature cycles between -20°C to +50°C to study the temperature-induced degradation on the detectors due to mechanical stress.

We describe a project to develop new medium-energy gamma-ray instrumentation by constructing and flying a balloon-borne Compton telescope using advanced scintillator materials combined with silicon photomultiplier readouts. There is a need in high-energy astronomy for a medium-energy gamma-ray mission covering the energy range from approximately 0.4 - 20 MeV to follow the success of the COMPTEL instrument on CGRO. We believe that directly building on the legacy of COMPTEL, using relatively robust, low-cost, off-the-shelf technologies, is the most promising path for such a mission. Fortunately, high-performance scintillators, such as Lanthanum Bromide (LaBr₃), Cerium Bromide (CeBr₃), and p-terphenyl, and compact readout devices, such as silicon photomultipliers (SiPMs), are already commercially available and capable of meeting this need. We have conducted two balloon flights of prototype instruments to test these technologies. The first, in 2011, demonstrated that a Compton telescope consisting of an liquid organic scintillator scattering layer and a LaBr₃ calorimeter effectively rejects background under balloon-flight conditions, using time-of-flight (ToF) discrimination. The second, in 2014, showed that a telescope using an organic stilbene crystal scattering element and a LaBr3 calorimeter with SiPM readouts can achieve similar ToF performance. We have now begun work on a much larger balloon instrument, an Advanced Scintillator Compton Telescope (ASCOT) with SiPM readout, with the goal of imaging the Crab Nebula at MeV energies in a one-day flight. We expect a ~4-sigma detection at ~1 MeV in a single transit. If successful, this will demonstrate that the energy, timing, and position resolution of this technology are sufficient to achieve an order of magnitude improvement in sensitivity in the medium-energy gamma-ray band, were it to be applied to a ~1 cubic meter instrument on a long-duration balloon or Explorer platform.

Gamma Ray Bursts (GRBs) are the strongest explosions in the universe which might be associated with creation of black holes. Magnetic field structure and burst dynamics may influence polarization of the emitted gamma-rays. Precise polarization detection can be an ultimate tool to unveil the true GRB mechanism. POLAR is a space-borne Compton scattering detector for precise measurements of the GRB polarization. It consists of a 40 × 40 array of plastic scintillator bars read out by 25 multi-anode PMTs (MaPMTs). It is scheduled to be launched into space in 2016 onboard of the Chinese space laboratory TG2. We present a dedicated methodology for POLAR calibration and some calibration results based on the combined use of the laboratory radioactive sources and polarized X-ray beams from the European Synchrotron Radiation Facility. They include calibration of the energy response, computation of the energy conversion factor vs. high voltage as well as determination of the threshold values, crosstalk contributions and polarization modulation factors.

The detection of fast neutrons has important applications in a wide variety of fields including geospace physics, solar physics, planetary, and applications within Defense and Security programs. Scintillator-based technologies have a proven record for detecting and measuring fast neutrons. They have high stopping power, good energy resolution, and fast timing properties. Modern organic scintillators such as stilbene and p-terphenyl, provide improved light output and pulse shape discrimination — the ability to distinguish gamma- from neutron-induced signals. Furthermore, modern readout devices such as silicon photomultipliers offer an ideal alternative to photomultiplier tubes given their inherently compact size and low operating voltages. The combination of modern scintillators and silicon photomultipliers enables new instrument designs for small satellite platforms such as CubeSats. We present the performance of a double-scatter neutron spectrometer based on p-terphenyl equipped with silicon photomultipliers. We also present preliminary results for pulse-shape discrimination using advanced waveform digitization techniques.

A natLiCl-BaCl2:Eu2+ eutectic scintillator was synthesized by the vertical Bridgman method aiming at the application of thermal neutron detection. The molar ratio of LiCl and BaCl2 was 75.1/24.9, which corresponds to the eutectic composition in the LiCl-BaCl2 system. The grown eutectic showed a periodic microstructure of BaCl2:Eu2+ and LiCl phases with 2-3 µm thickness. The a-particle induced radioluminescence spectrum of the scintillator showed an intense emission peak at 406 nm due to the Eu2+ 5d1-4f emission from the BaCl2:Eu2+ phase and an additional weak emission peak at 526 nm. The scintillation decay time was 412 ns. LiCl-BaCl2:Eu2+ eutectic samples exhibited non-correlated neutron detection efficiency and light yield as a function of crystal length, suggesting material non-uniformities within the boule. The light yield was equal to or greater than that of Nucsafe lithium glass and five times greater than that of scintillating lithium indium diselenide. Gamma-ray exposures indicate that gamma/neutron threshold discrimination for higher energy gamma-rays will be limited.

Fundamental changes in neutron detection technology were triggered by the extremely limited availability and raising price for 3He. Modern neutron Multi-Wire-Proportional-Chambers (MWPC) based on 10B4C coatings in inclined geometry are distinguished by their position resolution, which surpass by one order of magnitude that one of 3He tubes at comparable detection efficiency [1]. Thin-film preparation and analysis of 10B4C coatings came in to the fore of the R&D activity for these novel detectors. This activity is performed as an in-kind contribution to the ESS instrumentation, and is part of the German support to the ESS Pre-Construction Phase and Design Update [2]. Neutron conversion layers of 10B4C have been developed and deposited with thicknesses of up to 10 μm on pretreated Al substrates (300 μm thickness) with thickness uniformity better than 2 % over the entire deposition area of 1430 mm x 100 mm [3]. The 10B4C coatings show excellent adhesion to the flexible substrate even under strong externally applied stress or strain. The chemical and isotopic compositions of the 10B4C coatings were investigated by means of XPS, SIMS, and RBS and are in the range of requirements or better [1]. The manufactured coatings have been applied in two neutron detector concepts based on inclined and perpendicular neutron incidence on the converter coating. Measurements on neutronic properties, which were obtained by ToF-experiments at REFSANS in MLZ (Munich) show a quantum efficiency of up to 90 % (compared to an 1 inch 3He tube (10 bar)). This efficiency was measured for a 1.2 μm thick 10B4C converter coating at small angles of incidence (αi = 1 deg.) of the neutron beam with respect to the converter surface. The position resolution achieved by the investigated detector concepts ranges from 4 mm down to the sub-mm range. The investigated detector concepts have the potential to replace 3He detectors at the ESS and are planned to be utilized at the BEER beamline.

In this study, we compared neutron/gamma-ray discrimination capabilities of conventional bulk organic crystalline scintillators, anthracene, stilbene, and p-terphenyl. In scintillation spectra, emission wavelengths of anthracene, stilbene, and p-terphenyl were 450-520, 400-500, and 350-450, respectively. Scintillation light yields of anthracene, stilbene, and p-terphenyl under 137Cs gamma-ray irradiation resulted 20100, 16000, and 19400 ph/MeV, respectively. Then, 252Cf neutron or 60Co gamma-ray excited scintillation decay times were evaluated. Finally, based on these scintillation properties, neutron/gamma-ray discrimination was examined by using pulse shape discrimination technique. As a result, neutron and gamma-ray events were clearly separated in two-dimensional plot on pulse heights of fast and slow shaping times. In the conference, basic scintillation properties and neutron/gamma discrimination capabilities will be discussed.

A two-dimensional gas-based neutron detector system that can be operated under high-pressure was developed, and an irradiation experiment was performed using a Cf-252 neutron source. In a two-dimensional gas-based neutron detector, the thickness of the conversion gap should be made as small as possible to prevent the occurrence of the parallax effect of incident neutrons. To achieve performance such as a detection efficiency higher than 80% for neutron wavelength at 1.8 Å, it is necessary to increase the gas pressure of the detector. Therefore, we have developed a pressure vessel for a two-dimensional neutron detection system with individual signal line readout. There is a problem with increasing the gas pressure that the output signal strength decreases as a result. To measure output signals under high gas pressures, the supply voltage must be increased to boost the gas gain of the detector element. Therefore, we have also developed a dedicated two-dimensional multiwire-type detector element for individual signal line readout to ensure that the detector system can be operated satisfactory even at high pressure. The signals from neutrons clearly observed and can be discriminated from background signals such as gamma-ray and electrical noises. The flat-field image showed good homogeneity and an average gain spread of approximately 7.7%. The system exhibits a gamma-ray sensitivity of 1.1 × 10 ^-7.

A two-dimensional scintillation neutron detector that has neutron-sensitive area of 64 x 64 cm2 was developed for thermal neutron scattering instruments. The detector extensively used ZnS scintillation screens doped with 10B or 6Li and wavelength shifting fibers technology. The detector is designed to have a pixel size of 20 x 20 mm2 to cover a large area with a small number of electronics channel for demonstration. The scintillation light was read out from both sides of each WLS fiber in order to increase a collected light. The prototype detector exhibited a detection efficiency of 50% for 1.9-A neutrons, which was similar to the detector developed in the past that has a neutron-sensitive size of 26 x 26 cm2.

A variation of the RadICAL (Radiation Imaging Cylinder Activity Locator) system capable of performing in a dynamic environment, such as the environment created by active interrogation techniques, has been developed. RadICAL is a novel method for locating a radiological source (gamma) using a rotating detector element. The detector geometry is that of a thin sheet and is rotated to present a constantly changing surface area to the source; it therefore generates a characteristic temporal response which can be used to determine the source direction. The time required to determine the direction of a source make it unsuitable for dynamic environments and so an alternative method is presented that uses a stack of identical scintillator slabs in static positions at fixed horizontal angles around a central axis. By comparing count rates from each slab to a standard response curve, using a specially developed algorithm, the direction of a source can be determined without the need to rotate the detector. EJ299 plastic scintillator was used to allow detection of separate neutron and gamma events in a mixed field through pulse shape discrimination. Modelling and experiments were conducted to determine the design requirements of the system. This included an investigation into the optimum number of detector elements required as well as suitable detector geometry to achieve both angular resolution and effective pulse shape discrimination. A four element detector was built and shown to achieve an angular resolution of approximately 3 degrees when exposed to a 370GBq Cf252 source at distances of up to 4m.

When the CSNS (China Spallation Neutron Source) was planned, a new WNS (white neutron sources) based on the target reflected neutrons is proposed. The neutron energy has a wide distribution from eV to 200MeV. Several detectors are under R&D in this new neutron beam line. The neutron induced charged particle detector is one of them to detect the charged products of the target reaction with neutrons. The charged particle detector consists eight three stage telescopes, placed in a vacuum chamber. The telescope has a gaseous detector, a silicon PIN and a thick CsI(Tl) scintillator. To achieve low energy neutron reaction results, the gaseous detector employs a ultra-thin window of 0.5µm Mylar. It has a very low energy threshold to the particle discrimination (about 500keV for protons), and a relative higher stopping power for 100MeV protons.

Various geometries of neutron focusing mirrors have been proposed to increase the neutron flux since the existing neutron sources have a much lower brilliance than synchrotron X-ray sources, especially the compact neutron sources. We applied the ellipsoidal mirrors to the design of Small Angle Neutron Scattering (SANS) instruments at Compact Pulsed Hadron Source of Tsinghua University and a lot of ray-tracing simulations have been carried out to optimize the geometry and analyzed the relationships between the performances of SANS instruments and geometrical parameters of nested ellipsoidal mirrors. Ellipsoid-shaped conical mirror was proposed to overcome the difficulty of fabricating highly aspherical mirrors, such mirrors are easier to fabricate and to be nested. The aberration of the ellipsoid-shaped conical mirror was analyzed and evaluated.

The reduced availability of ³He is a motivation for developing alternative neutron detectors. ⁶Li-enriched CLYC (Cs₂LiYCl₆), a scintillator, is a promising candidate to replace ³He. The neutron and gamma ray signals from CLYC have different shapes due to the slower decay of neutron pulses. The long decay time associated with the scintillation emission of CLYC often results in pulse pileup for event rates exceeding 100 kHz. Discriminating neutrons in a mixed field of gamma rays and neutrons is a challenging task especially when the event rate is high. There have been other methods that successfully distinguish neutrons at less than 100 kHz event rates, but separating them at higher event rates has not been satisfactory. In this work, we propose an algorithm that discriminates the neutron events directly based on their decay time and energy spectral density (ESD). The approach is assessed with data collected for different event rates (13 kHz to 1660 kHz) for an average data record length of about 750 ms in each case, providing more than 100,000 events to analyze. The results show accurate clusters of neutron events in the pulse shape discrimination (PSD) plot even during high event rates, and the approach gives a uniform figure of merit (FOM) ranging between 1.28-1.35 for all event rates.

Chinese Spallation Neutron Source (CSNS) was under construction since 2008. The General Purpose Power Diffractometer (GPPD) is one of the first spectrometers of CSNS. This instrument requires the neutron detectors with the cover area larger than 10m2, the neutron detect efficiency better than 50%, and the spatial resolution better than 5mm×10mm in horizontal and vertical directions respectively. Due to the shortage and the rapidly increasing price of the 3He gas, seeking new types of position-sensitive neutron detectors is urgent. The investigation of a large area scintillator neutron detector is developed to fulfill the requirements of the GPPD. It consists of two layers of 6LiF/ZnS(Ag) scintillators, two layers of crossed wave-length shifting fiber arrays, several multi-anode photo multiplier tubes (MA-PMT), and the ASIC readout electronics. A prototype with 250×500 mm2 incident area has been constructed, and the characteristics of the key components are studied. The detector has been tested with collimated neutron beam with wavelength of ? = 2.6 Å at three axis spectrometer in China Academy of Engineering Physics (CAEP). A position resolution of 4 mm and a neutron detect efficiency with better than 50% are obtained, which shows that the performance of this scintilltor neutron detector could fulfill the needs of the GPPD.

Novel neutron energy spectrometer using an onion-like single Bonner sphere was proposed in our group. This Bonner sphere has multiple sensitive spherical shell layers in the single sphere and can obtain information for estimation of a neutron energy spectrum in one measurement. In this spectrometer, a band-shaped thermal neutron detection medium, which consists of a LiF-ZnS mixed powder scintillator sheet and a wavelength-shifting (WLS) fiber readout, was looped to each sphere at equal angular intervals. However, since the LiF-ZnS mixed powder scintillator shows no characteristic shape in the pulse height spectrum, it is difficult to set the pulse height discrimination level. In order to solve this problem, we replaced the LiF-ZnS mixed powder into a flexible and Transparent RUbber SheeT type LiCaAlF6 (TRUST LiCAF) scintillator. TRUST LiCAF scintillator can show a peak shape corresponding to neutron absorption events in the pulse height spectrum. To uniform the directional sensitivity, an amount of LiCAF neutron converter is reduced near polar region, where the detector media are concentrated. We fabricated the prototype detector with five sensitive layers using TRUST LiCAF scintillator. In this paper, we characterize the fabricated detector. We check the directional uniformity and the neutron energy dependence of the detector sensitivity. The detector shows excellent directional uniformity in the neutron sensitivity. We confirmed that the measured energy response, which was evaluated at monoenergetic neutron sources, agrees with the simulated one, which was calculated by Monte Carlo simulation code PHITS.

A resonance neutron imaging system has been developed based on combination of a glass based Gas Electron Multiplier (glass GEM) detector and a resonance filter. Neutrons passed through the resonance filter are detected by the glass GEM detector, which is a two-dimensional neutron detector with a neutron-charged particle converter and has capabilities of a lower gamma-ray sensitivity. The resonance filter decreases an incident neutron flux corresponding to a resonance peak in the cross section of nuclear reactions with neutrons. However, a conversion efficiency in the neutron-charged particle converter for these neutrons is lower than that for lower energy neutrons, which also have the capability of passing through the filter. To suppress background counts caused by the lower energy thermal neutrons, a thermal neutron shield material is located behind the filter. Therefore, counting the incident neutrons in the glass GEM detector with the shield material, neutron spatial distribution in energy of the resonance peak can be estimated by net counts between with and without the resonance filter. Previous works have used a GEM detector made of polyimide as the neutron detector and assessed the performance for the epithermal neutron detection using the accelerator-based neutron source at KURRI. While the GEM detector has disadvantages of a low tolerance to discharges and makes out gases, the glass-GEM is tolerant to the discharge and is capable of sealed operation. We made the prototype system with the glass-GEM detector and evaluated its detector response using the Ag resonance filter at KURRI. In addition, we made Monte Carlo simulations of the detector response to neutron using PHITS. As a result, the simulation results agreed with the measured detector response, which shows the ability of the neutron imaging in energy of the resonance peak. The optical readout system for light emitted from the glass-GEM detector also developed toward resonance neutron imaging.

Neutron detection is of particular interest for nuclear or radiological material identification for security and proliferation deterrence, as well as for nuclear waste detection and monitoring. We present a concept for a Field-Deployable Imaging Neutron Detector (FIND) based on modern, commercially available detector technology that is compact, low-power, low-mass, and rugged. Individual detector cells are composed of plastic scintillator with pulse-shape discrimination (PSD) ability read out by arrays of silicon photomultipliers (SiPMs). A double-scatter neutron camera is formed by two layers of such detector cells. The compactness, ruggedness, and low weight of this technology allows these layers to be easily transported in standard portable containers for rapid deployment and assembly in the field. We describe the FIND instrument concept and initial tests of detector cell performance.

One of the fast neutrons detection method relies on activation of ¹⁹F nuclei in the scintillator medium. The technique, known as threshold activation detection (TAD), can be applied for prompt photofission neutrons detection emitted from nuclear materials concealed in cargo equipment. As a results of the ¹⁹F(n,a¹⁶N or ¹⁹F(n,p)¹⁹O reactions with half-life of 7.1 s and 26.9 s, respectively, ß particles with the maximum endpoint energy of 10.4 MeV are emitted. Main benefits of this method are that the beta particles – prompt neutron signatures – can be registered when the beam from the linear accelerator is off, the prompt neutrons carry higher amount of energy and their number per fission is two decades greater in comparison with the delayed neutrons. In this paper, we compare the response of novel 2” in diameter and 2” height fluorine based plastic scintillator (F-plastic) with the fluorocarbon EJ-313 and classical PVT-based EJ-200 scintillators after short exposition on 14.1 MeV neutrons in order to observe the contribution of the ß continuum to the recorded spectra.

We report on the measurements of neutron spectra from a Cf-252 spontaneous fission source using a Li-doped glass–polymer composite scintillation detector. The composite detector uses both pulse height and pulse shape to achieve excellent gamma-neutron discrimination with fewer than one out of every 10^8 gamma events misidentified as a neutron. The cylindrical detector is 5.05 cm in diameter and 5.08 cm in height and was fabricated using 1-mm diameter Li-doped glass rods and scintillating polyvinyltoluene. Geant4 simulations were conducted to set the capture gating time acceptance window and to correlate the scintillation yield originating from thermalization to the incident neutron energy spectrum. We discuss the results of simulations and the preliminary spectroscopic experimental results.

³He gas proportional counter has been used as the basic sensors for neutron detection. Recently, the application of the ³He detectors is decreasing due to ³He supply crisis and high security demands for its handling. In our previous studies, the Eu²⁺ and Ce³⁺ doped LiCaAlF₆ (LiCAF) scintillator crystals have been developed as an alternative material to 3He gas proportional counter. These fluorides possess high light yields, large capture cross-sections for thermal neutrons, and non-hygroscopic nature. However, the recent usage of Eu and Ce, as members of the rare earth (RE) elements in various fields, is being limited due to continuous RE supply crisis. Therefore, search for alternative doping element with equivalent properties is required. In this work, we focused attention on Sn as a new activator. Sn doped optical materials have been reported as represented by Sn:KCl, Sn:KBr and Sn:KI. Therefore, Sn doped LiF and LiCAF single crystals were grown and their optical and scintillation properties were investigated. Sn doped LiF and LiCAF single crystals were grown by the µ-PD method. During the crystal growth, a liquid-solid interface was stable below the carbon crucible. Diameters of the as-grown crystals were approximately 2 mm and they were colorless and high transparency. There was no visible crack and inclusion in the crystals. The radioluminescence (RL) spectrum of Sn0.5%:LiCAF crystal under ?-ray irradiation was measured. In the RL spectrum, emission peaks around 270 and 310 nm were observed. These emission peaks are considered to be attributable to the Sn²⁺ ion. Results of other scintillation and luminescence properties for Sn:LiF and Sn:LiCAF single crystals will be reported.

A desire for a highly efficient, low-power, compact thermal neutron detection system with excellent gamma-ray discrimination is still desired for a variety of applications. One current avenue being pursued is the development of semiconductor-based neutron detectors. Because of the higher density of the sensing material, these detectors can have a higher detection efficiency than conventional gas-filled detectors. However, a required trait of thermal neutron-sensitive semiconductor detectors is that their charge collection properties must be sufficient for high detection efficiency. Boron carbide is a p-type semiconductor that has the potential for having the highest intrinsic neutron detection efficiency of any neutron sensor. Boron carbide is commonly used as an amorphous coating in various detection systems, but the development and implementation of truly semiconducting, single crystal boron carbide has yet to be realized. This presentation will report on the current progress of single crystal boron carbide growth via hot filament chemical vapor deposition (HFCVD) for neutron detection applications.

Superheated droplet detectors (SDDs) are composed of superheated droplets suspended within a host gel and have been widely used for fast neutron dosimetry measurements. While these detectors have good sensitive to fast neutrons, they lack efficiency for the detection of thermal neutrons. For improving the sensitivity to thermal neutrons of SDDs, boron or lithium could be doped into the detector. To evaluate the potential intrinsic efficiency of such devices, simulations were performed on four different types of detectors (boron or lithium doped in either the droplets or the gel). The results show that the detector with ¹⁰B doped in the droplets has the highest intrinsic detection efficiency for thermal neutrons. These results, verified with experiment, shall be presented in this paper.

Fricke–xylenol–orange gel dosimeters with planar geometry (3 mm in thickness, many centimeters in diameter) have shown noticeable potentiality for dosimetry in phantoms exposed to the epithermal neutron beams of research reactors. In fact, it is possible to achieve images of the spatial distribution of the gamma dose, the neutron dose and the dose due to the charged particles generated by thermal neutron reactions. Thanks to the planar geometry, the neutron transport in the phantom is not sensibly affected by the change in the gel matrix isotopic content performed to separate dose contributions. This was confirmed by the results of Monte Carlo (MC) simulations. These dosimeters have proved to be a valid tool for measurements in water phantoms irradiated with the epithermal neutron beams of a research reactor. The main uncertainty of the obtained results comes from the scarce knowledge of the dependence of the gel-dosimeter sensitivity on the linear energy transfer (LET) of the radiation and this study is in continuous progress by our research group. The reliability of the results obtained utilizing these dosimeters with planar geometry for in-air measurements aimed at neutron beam characterization has been investigated too. No change in gamma dose has been evidenced, but a consistent enhancement of the thermal neutron fluence has been found with the proposed planar geometry of gel dosimeters. Suitable MC calculations have been developed to investigate the dependence of thermal neutron rise on the dosimeters thickness or shape. The reduction of the dosimeter thickness has not shown noticeable advantage. On the opposite, Fricke xylenol orange gel dosimeters of cylindrical shape, enclosed in transparent cylindrical tubes with external diameter of 3 mm, have shown to induce no alteration of the thermal neutron fluence. The obtained results show that gel dosimeters with suitable design can be a valid support for epithermal neutron beam dosimetry.

Neutron diffractometers are part of the instrument suite of all current major neutron facilities. The extensive applications of neutron diffraction in material science, physics, chemistry, mineralogy, and engineering led naturally to the decision that the ESS diffraction reference suite as presented in the Technical Design Report shall be covered by five instruments. These instruments must be able to use efficiently the long and intense ESS pulse. This implies that the detector system must be able to cope with a high dynamic range of intensities emitted by the sample. This high dynamic range results from a broad range of scattering cross-sections of samples and the high neutron flux envisaged at the ESS. During the selection round held in 2013-2014, three diffraction instruments were recommended by the ESS Scientific Advisory Committee to enter the preliminary construction phase in 2015-2016. Results of McStas or Vitess simulations of the proposed instrument concepts indicate that the expected fluxes on the samples are up to two orders of magnitude larger than the current limit at other neutron scattering facilities. In this paper we will review and discuss in detail the rate requirements for the detection systems at the future ESS diffractometers and compare them to real data from reference samples taken at existing instruments. Based upon these findings, we will also present the strategy for detector and readout electronics developments by ESS and In-Kind partners in order to meet the high rate capability and other detector requirements for neutron diffraction instruments. The ¹⁰Boron-detector technology is favored, owing to the encouraging results from efficiency and gamma-sensitivity measurements obtained with realistic size demonstrators, as well as radiation hardness tests on ¹⁰B₄C-thin films.

The European Spallation Source (ESS), currently under construction in Lund, Sweden, will house a suite of 16 user instruments for neutron scattering experiments. The spallation source of the ESS will emit relatively long, 2.8 ms, neutron pulses with an integrated flux that will greatly exceed that of current facilities. This leads to both large advancements in instrument performance as well as to increased length and complexity of the beam delivery systems. The instruments will each be equipped with neutron beam monitors used for data normalisation and analysis, as well as commissioning and diagnostics. In this paper we present the requirements for beam monitors for the ESS and the strategy to meet these in a standardised approach. A large range of specifications in efficiency, dynamic range, time and position resolution, compatible materials are needed. A new feature for neutron beam monitors for some locations, is the ability to measure time profile of each source pulse individually. In general, event mode readout will be used for monitors, similarly to other neutron detectors at the facility. A selection of detectors based on different technologies will be available. Monitors will be integrated with beam lines and choppers in a way that allows to freely choose the type of monitor based on final requirements of an instrument. For this end, space for a standardised module, housing a monitor will be provided in conjunction with chopper assemblies and elsewhere on each beam line.

The pulsed neutron transmission spectroscopic radiography is attractive in the research fields of energy-resolved neutron radiography. The imaging technique is based on the energy-analysis of neutrons by time-of-flight (TOF) method. The neutron transmission spectrum includes the Bragg scattering edges with the crystallographic structure and texture information and the transmission dips due to the resonance absorption of the nuclei. We developed a high performance high-frame-rate camera for this neutron imaging at an electron linac pulsed neutron source in Hokkaido University and showed usefulness of the system by Bragg edge measuremnts. Our imaging system consists of a neutron image intensifier, a high-frame-rate CMOS camera, a frame accumulator and a personal computer for image data recording. The high-speed CMOS camera can take images of 320 x 240 pixels with 100kfps, 512 x 512 pixels with 30kfps or 960 x 960 pixels with 10kfps. The resolution is 12 bit. As the repetition rate of the linac is 25 Hz and the camera is operated with the peed of 100kfps, successive 4,000 frames are accumulated repeatedly over every 16, 64, 256, 1024, or 4096 linac triggers. Accumulated 16, 18, 20, 22, or 24 bit data are transferred to PC memory by high speed data link and next accumulation starts to achieve seamless data taking. The system was successfully used for experiments at the electron linac pulsed neutron source in Hokkaido University and it was proved that the function we intended worked well.

In recent years, the global shortage and increased cost of ³He has led to extensive research into alternative detection technologies for nuclear threat detection. The main alternatives currently being developed are based on ⁶Li or ¹⁰B capture reactions to detect thermal neutrons. One such detector is a novel thermal neutron detector developed by Los Alamos National Laboratory consisting of multiple spray coated ¹⁰B thin films combined with a double helix electrode configuration. The detector promises low manufacturing costs and is designed to fit into an existing high density polyethylene moderator housing used by two standard 2 bar ³He drift tubes, making this a potential direct replacement for many current portal scanning modules. Also of interest is the dual neutron gamma detector Cs₂LiYCl₆ (CLYC), which has the ability to discriminate between neutron and gamma interactions and has spectroscopic performance surpassing common alkali-halide scintillators such as NaI(Tl). In this work a calibrated neutron facility was used to measure the intrinsic neutron detection efficiency when exposed to ²⁵²Cf and ²⁴¹Am/⁹Be and the gamma rejection performance was assessed through the use of two ¹³⁷Cs sources. In addition a commercially available ³He detector module was fielded to provide a direct comparison.

Whole-energy spectral information of the quasi-monoenergetic high-energy neutron field generated by the ⁷Li(p,n) reaction is required for testing and calibrating neutron detection devices for the purposes of physics research and radiation protection, because the neutron field consists of a monoenergetic high-energy peak and an unwanted continuum down to the low-energy region. In this study, spectral measurements were performed by the time-of-flight (TOF) method using an organic liquid scintillation detector and a Li-glass scintillation detector above 100 keV, and the unfolding method using an activation Bonner sphere spectrometer (BSS) for whole energy region. As the Bonner unfolding method strongly depends on the default spectrum, the TOF-based reliable default spectrum can raise the precision of the unfolding. In contrast, measurement for the low-energy region below 100 keV depends on the Bonner unfolding method alone, because the room-scattered neutrons which lost their flight-time information are dominant below 100 keV. Therefore, especially in the low-energy region, evaluation of response matrix of the activation BSS is important. Dependence of the unfolding result on the response evaluation of the activation BSS will be discussed in this presentation, in addition to the results of the whole-energy spectrum measurement.

In this contribution we present neutron converters for larger area neutron detector applications that are developed using materials theory, advanced diagnostic techniques, and industrial production processes. Due to the urgent need for alternatives to 3He-based neutron detectors, a new generation of detectors uses thin films with a high neutron absorption cross section as the converting material. High quality thin films are essential ingredients in these detectors. The first choice of thin film material is 10B4C, which is deposited onto Al-blades or Si-wafers with the physical vapor deposition technique DC magnetron sputtering. One full-scale large area detector at the ESS needs in total ~1000 m2 of two-side coated Al-blades with ~1 um thick 10B4C films. This presentation will discuss the tough demands on film purity and thickness uniformities and the challenge to upscale the process in order to have the first detectors ready for use at the ESS already at the end of this decade. In the context of this challenge, ESS has recently commissioned a deposition facility, adjacent to Linkoping University, based upon industrial techniques to provide the volume of coatings required for this strategic material. A wide variety of coatings have already been provided to the community developing novel neutron detectors; examples are shown. In particular, the ongoing work on expanding and qualifying the list of substrates on which such depositions can be made is shown, with teflon and glass taken as examples. Gadolinium converters are also of interest for some detectors requiring high position resolution. Methods to obtain and stabilise such convertor layers are shown. Finally, depositions of innovative GdN-based coatings are shown, as predicted from first principles calculations. Theory and experiments have throughout the work been applied in parallel to optimize the coating quality, in particular in terms of adhesion, thickness, composition, and neutron detection performance.

In the past few years, several interesting developments in microstructured solid-state thermal neutron detectors have been pursued. These devices feature high aspect-ratio cavities, ?lled with neutron converter materials, so as to improve the neutron detection ef?ciency with respect to planar sensors. In the framework of the INFN HYDE (HYbrid Detectors for neutrons) project, we have designed a new microstructured sensor aimed at thermal neutron detection and imaging, e.g., with a Medipix read-out chip, and featuring a good efficiency (~20%) while minimizing the process complexity. The sensor design and technology will be presented at the conference, along with selected results from simulations and from the initial characterization campaigns.

The Energy-Resolved Neutron Imaging System, RADEN, located at BL22 of the J-PARC Materials and Life Science Experimental Facility (MLF), started commissioning from November 2014 and began user operation in April 2015 as the world’s first dedicated high-intensity, pulsed neutron imaging beam line. In addition to conventional radiography and tomography, we use the wide bandwidth and accurate measurement of neutron energy by time-of-flight, made possible by the high-quality, pulsed beam at the MLF, to perform energy-resolved neutron imaging. Utilizing these energy-resolved techniques, we can directly image the macroscopic distribution of microscopic properties of materials in situ, including crystallographic structure and internal strain (Bragg-edge transmission), nuclide-specific density and temperature distributions (neutron resonance absorption), and internal/external magnetic fields (pulsed, polarized neutron imaging). To carry out such measurements in the high-rate, high-background environment at RADEN, we use cutting-edge detector systems, which have been recently developed in Japan, employing micro pattern detectors and high-speed Field-Programmable-Gate-Array-based data acquisition. Such counting-type detectors offer sub-µs time resolution, high data rates, and event-by-event gamma rejection, making them essential tools for energy-resolved neutron imaging at RADEN. The available detectors cover a range of spatial resolutions from 0.3 to 3 mm and counting rates from 0.6 to 10 Mcps, allowing us to match the best detector to the given experimental conditions. In this presentation, we will give a brief overview of RADEN and describe in detail the available counting-type detectors and their performance as measured during on-beam commissioning, including demonstrations of energy-resolved imaging measurements. We will also consider planned improvements to the detector systems and the expected increases in performance.

Abstract?Correlated neutrons from a Cf-252 spontaneous fission source were measured with a coincidence detection system. The system consisted of three EJ-309 cylindrical liquid scintillators (length and diameter of 7.62 cm) configured to quantify the effects of neutron cross-talk on the total observed correlated counts. Because scatter-based detectors are susceptible to neutron cross-talk, the discrimination between true correlated counts and cross-talk is significant for neutron coincidence measurements. This measurement aimed to mitigate the true neutron coincidences between detectors with adequate polyethylene shielding, and was compared to simulations. The fractional influence of cross-talk on the total observed correlated counts was 30% for neutrons above ~0.65 MeV at a detector-source-detector angle of 30?. Furthermore, the fractional influence of neutron cross-talk increases for decreasing detector-source-detector angles at a constant detector standoff. The angular distribution of the scattered neutron was also simulated, and shows an anisotropic distribution in the scatter detector frame of reference primarily dependent on kinematics of the neutron-hydrogen scatter and the detector volume. Index Terms? Angle, correlated counts, neutron cross-talk, neutron scatter.

Proton therapy facilities use high-energy proton beams to destroy cancerous cells with greater specificity than photon-based approaches. However, due to the high energy of these protons, secondary radiation is produced through interactions with the patient and surroundings. These secondary neutrons and photons need to be accurately characterized for the benefit of patients and medical personnel. Measurements have been performed at a Chicago Proton Center proton therapy treatment beamline. Continuous-operation pencil beams of 155- and 200-MeV protons were used to irradiate three tissue-equivalent phantoms provided by CIRS Inc: soft tissue, compact bone, and trabecular bone. Secondary particles were detected using an array of organic scintillation detectors: three 7.6-cm diameter by 7.6-cm thick EJ-309 liquid scintillators and one 5-cm diameter by 7.6-cm thick stilbene crystalline scintillator. Pulse shape discrimination was applied to each detector using a charge-integration technique. Preliminary analysis has shown clear separation in the measured neutron and photon pulses. The results presented in the full paper will contain a detailed comparison between the simulated and measured neutron spectra.

Dual plane neutron scatter cameras have shown promise for localizing fast neutron sources. The condition that a neutron must scatter in both planes of the camera produces low counting efficiencies. Counting efficiency can be improved using an alternative design that uses a single, optically segmented volume of scintillation material. Using Geant4, we simulated pulses from neutron elastic scatter events at different locations throughout an EJ-204 scintillator bar. We used nonlinear regression on low light pulses to determine the position along the bar where the scatter event occurred.

Abstract— Single-crystal uranium dioxide prepared by the hydrothermal synthesis technique is a novel solid-state material with potential for neutron detection. Simulations of an envisioned detector using GEANT4 and TCAD modeling indicate that charge deposition and device response would distinguish neutron fission events unambiguously from gamma events and that the device performance would be largely dominated by carrier transport and not charge deposition from fission fragment kinetic energy loss. The nearly ohmic current-voltage (I-V) response of an as-grown crystal using mechanical tungsten contacts portends successful device application.

Fast neutrons created by muogenic processes produce a depth dependent background for rare-event neutral particle detectors. At all depths, measurements are sparse, never with the same detector, and where multiple measurements exist the fast neutron background lacks consensus on the spectrum and rate anti-coincident from the initiating muon. To solve the discrepancy between measurements, a fast neutron spectrometer has been constructed using a lead-based spallation amplifier to convert single fast neutrons into multiple lower energy secondary neutrons. Secondary neutrons then capture in a gadolinium doped scintillator. The secondary neutron signal with a Geant4 model are used to unfold the incident neutron energy. The detector consists of two plastic scintillator modules measuring 1.0x0.75x0.02m³ which surround a lead block. Measurements were performed at the Kimballton Underground Research Facility (KURF) over 2 years at 3 different depths. Results from measurements at 380 and 600 m.w.e. will be presented. Preliminary results from 1450 m.w.e. and an above ground verification measurement will additionally be presented. The results from these measurements will be used to create background models for future large anti-neutrino detectors which are capable of detecting and monitoring nuclear reactors.

Alternatives to 3He are being investigated for gamma-ray insensitive neutron detection applications, including plutonium assay. One promising material is lithium-6 fluoride with silver activated zinc sulfide 6LiF/ZnS(Ag) in conjunction with a wavelength shifting plastic. Doping the 6LiF/ZnS(Ag) with nickel (Ni) has been proposed as a means of reducing the decay time of neutron signal pulses. This research performed a pulse shape comparison between Ni-doped and non-doped 6LiF/ZnS(Ag) neutron pulses. The Ni-doped 6LiF/ZnS(Ag) had a 32.7% ? 0.3 increase in neutron pulse height and a 32.4% ? 0.3 decrease in neutron pulse time compared to the non-doped 6LiF/ZnS(Ag). Doping 6LiF/ZnS(Ag) with nickel may allow neutron detector operation with improved signal to noise ratios, and reduced pulse pileup affects, increasing the accuracy and range of source activities with which such a detector could operate.

A spectroscopic radiation detection system with particle identification capabilities is presented for use in neutron detection applications including nuclear physics experiments and non-destructive material evaluation. Detector modules consisting of silicon photomultipliers (SiPMs) coupled to newly developed plastic scintillators demonstrate good gamma-neutron separation and neutron energy threshold below 120 keV electron-equivalent energy. Particle separation is achieved by pulse shape discrimination (PSD) and quantitatively characterized by its figure of merit (FOM). We present measurements completed using a mixed gamma-neutron 241Am-Be(a,n) source and monoenergetic neutron beams between 8 MeV and 20 MeV. Several commercially available optical detectors are compared to custom CMOS fabricated optical devices. These devices were found to perform as good as or better than a super bialkali photomultiplier tube (SBA-PMT) with a FOM as high as 2.0 at 1 MeVee.

Silicon carbide-based devices have experienced in the last decades a big interest because of the peculiarities of such a semiconductor: large band gap energy, good thermal conductivity and high atomic displacement energy. Thanks to these properties, nowadays, SiC represents a real alternative to conventional neutron semiconductors detectors mainly in harsh environments as nuclear reactors, outer space and in-depth gas and oil prospecting. In the framework of the European I_SMART project, we have designed and made new SiC-based nuclear radiation sensors able to detect both fast and thermal neutrons and record gamma-rays contribution. Our sensor is based on a p-n junction, where electrons generated in the space charge region (SCR) can be collected, and the signal recorded. Such diodes have been tested under different irradiation sources showing their stability (same electrical-behaviour before and after thermal neutrons irradiation with a flux of 7x108 neutrons/s·cm2); fast neutron generator at the KIT in Dresden to study the stability at very high temperatures and the fast neutron generator at Schlumberger facility in Clamart, France. In the latter case, our sensor could be tested in quasi-realistic working conditions for the oil and gas prospecting, with temperatures up to about 150°C, and with a flux, for 14 MeV neutrons, of 108 neutrons/s over 4p steradian. Different geometries of our sensors have been tested. The low value of the flux has demanded large active area diodes in order to get significant spectra. Different available geometries as well as the possibility to intervene on the size of the diode, the dose of the converter element (10B in our case) all represent strengths of our system which can be customised according to the needs of the working conditions. These experiments show the skills of the I_SMART SiC-based devices to operate in harsh environments, whereas other materials would strongly suffer from degradation.

LUPIN-II is a novel rem counter specifically conceived to work in pulsed neutron fields (PNFs). The latest version of the detector, which was first developed in 2010, includes some modifications in the acquisition electronics and in the analysis method that improve its performance in terms of maximum neutron H*(10) per burst that can be detected in PNFs without suffering from underestimation effects(currently around few nSv per burst for commonly available rem counters) and gamma rejection properties. The detector is available in two versions, employing either a BF3 or a 3He proportional counter, which can be chosen based on the sensitivity and the geometrical dependence requirements. Due to its intrinsic characteristics, LUPIN-II can be employed both as a radiation protection device, as a supporting device for least intrusive beam monitoring technique, and as a beam loss monitor. The acquisition electronics has in fact been modified in order to generate an alarm signal within 50 ms. The results of several measurement campaigns performed in the most different radiation environments are presented, including experiments performed around medical linear accelerators (LINACs), synchrotrons and free electron laser (FEL) accelerators.

Neutron radiography has been in use for many decades and is often used for non-destructive analysis. For Fast neutrons of initial energy typically ranging from 2.5 MeV (D-D reaction) to 14.1 MeV (D-T reaction) are used to image large, dense objects that would otherwise attenuate cold or thermal neutron sources. In previous fast neutron radiography, time-of-flight principles have been applied to identify materials (based on differences in material transmission properties) with neutron sources of energy up to 14.1 MeV or to reject scatter with neutron sources of energy up to 10 MeV. TIGRESSE (TIme Gating to REject Scatter and Select Energy) is a radiography system currently being developed at Los Alamos National Laboratory that can both identify materials and reject scatter using neutrons of energy up to 600 MeV. By employing a fast scintillator converter and a neutron source of high energy, high repetition rates, and narrow pulses, a specialized intensified charge coupled device (iCCD) camera can be gated in time to reject slower scatter and, with a polychromatic source, to vary material transmission. Novel proof-of-principle experiments were successfully conducted at the Los Alamos Neutron Science Center (LANSCE) in January, 2015 which generates spallation neutrons via 800 MeV protons incident on a tungsten target. The imaging experiments were conducted in Flight Path 15R, which sees neutrons ranging in energy from 100s of keV to 600 MeV. LANSCE has very fast timing (1786 ns micropulse width, 625 ï¿½s macropulse width, operated at 50 or 100 Hz) that made it viable for time-of-flight imaging. Time-gated images were successfully taken of three object configurations, and were obtained in 36 min or less, with some in as little as 6 min. Future work (simulation and experimental) is being undertaken to improve camera shielding and system design and to precisely determine optical properties of the imaging system.

LET is a direct geometry cold neutron spectrometer at the ISIS spallation neutron source, working in the range between 0.5 and 30 meV (1.6 to 12.8 Å). The development and installation of a large area neutron detector array for LET has recently been completed. The detector array consists of 384 3He filled resistive wire tubes, 4 m long and25.4 mm in diameter. The 3He pressure is 10 bars to guarantee an efficiency above 90% for 1.6 Å neutrons and 3 bars of argon are added as a stopping gas. The tubes are organised in twelve panels installed inside the LET vacuum tank that is operated at cryogenic vacuum. Here we will report about the assembly and test of the LET detectors before their installation on the instrument and their performance on LET. The two main tasks in the assembly of the detectors were: align the support of the tubes with a precision better than 0.5 mm along the 4 m length of the tubes and guarantee the vacuum tightness for all the ~2000 vacuum feeds-through. We will outline the methods used to achieve these results and the tests performed to check these requirements before the installation of the detectors on the instrument. Regarding the operation of these detectors on LET, we will describe the digitisation and processing of the signals from the tubes. In particular we will focus the attention on how the signal processing is optimised to operate these detectors at high neutron rates whilst preserving other performances like gamma rejection and position resolution.

One of the capabilities of diamond detectors is the measurement of neutron radiation, due to their carbon composition. In these work is described a campaign of measurements related with neutron irradiation using different sources: starting with a 252Cf standard neutron source, continuing with a wellknown nuclear reaction at a low-energy tandem accelerator and finishing with neutron radiation produced in a hospital radiotherapy machine. The aim of all these measurements is to evaluate the qualities of diamond device to detect neutron irradiation, thus proving they are good candidates to be used as neutron dosimeters at hospital accelerators. Our preliminary results show that diamond detectors are a promising tool to be implemented in such a kind of facilities.

Neutron multiplicity counters are used in safeguards to provide rapid assay of samples which contain an unknown amount of plutonium in a potentially unknown configuration. With appropriate detector design, the neutron single, double, and triple coincidence events can be used to extract information of three unknown parameters such as the ²⁴⁰Pu-effective mass, the sample self-multiplication, and the (a,n) rate. Alternatives to ³He have been investigated for next-generation neutron multiplicity counters. A project at PNNL is using nickel-quenched ⁶LiF/ZnS neutron-scintillator sheets and wavelength shifting plastic for light pipes in place of ³He. A combination of laboratory and modeling work predicts a LiF/ZnS-based system to be able to match or exceed the performance of the best ³He-based systems available. Also, the Ni-quenched material is expected to allow for improved neutron/gamma-ray discrimination at twice the event rate relative to the non-Ni-quenched LiF/ZnS. A new system based on the LiF/ZnS material is under construction and components are being used to optimize the detection efficiency and neutron/gamma-ray discrimination properties. The full-scale system has been extensively modeled to better understand the impact of all the various components. The new system is partially constructed and is undergoing performance testing utilizing high-speed digitizers with field programmable gate arrays to perform the neutron/gamma-ray discrimination. The measured properties of the new system will be presented and used to determine the expected performance of the full-scale system due for completion in 2016.

It has been shown that the alpha – gamma pulse shape discrimination (PSD) in LaBr:Ce can be significantly enhanced by Ca or Sr co-doping. Enhanced alpha-gamma PSD makes it possible to create a high performance neutron-gamma dual mode detector using co-doped LaBr3:Ce and a surrounding neutron conversion layer. In this study, a compact neutron-gamma detector is constructed by a co-doped LaBr3:Ce crystal and a 6LiF conversion layer. Performance of the detector is optimized by precise control of the thickness of the 6LiF layer and detector geometry based on simulation results. Detector performance results on PSD figure of merit, neutron detection efficiency and gamma rejection ratio are presented.

Neutron generators are widely used in security applications, industry, medicine, and research. The neutron based methods require precise measurement of neutron yield to normalize the measured data. To address this need, the technology of fast neutron flux monitoring was developed. The output of DD and DT neutron generators was characterized using the EJ-299-33A plastic scintillator. This detector enabled fast neutron count rate measurements and spectroscopy. Monoenergetic neutron response functions were measured using the accelerator based source for neutron energies between 0.1 MeV and 20.2 MeV with a gap between 8.2 MeV and 12.2 MeV responses. The T(p,n)3He, D(d,n)3He, and T(d,n)4He reactions were employed. Digital pulse shape discrimination was used to separate the neutron component of the measured responses. The experimental neutron responses were used in carrying out spectral unfolding technique based on polynomial fitting. The unfolding technique was experimentally verified using DD and DT sources.

The use of single particle counting hybrid pixel detectors based on neutron conversion into energetic light ions has opened possibilities for neutron detection with wide dynamic range, excellent linearity and spatial resolution in the micrometer range. A significant limitation in the applicability of this detector technology in various neutron-based techniques has been, however, the rather small sensitive area of a single detector (~ 2.2 cm2). For this purpose, the large area imaging detector WidePIX was developed which consists of a matrix of sensitive detector tiles (each tile consisting of a single Timepix device equipped with an edgeless silicon sensor) without spacing gaps or insensitive areas. The technology of edgeless semiconductor sensors together with precise alignment method and multilevel architecture of readout electronics result in practically continuous fully sensitive detector area. In this contribution we present the experimental results obtained with such large area pixel detector adapted for thermal neutron imaging by deposition of a 6LiF neutron conversion layer onto its surface. We make use of a newly developed neutron detector consisting of 20 Timepix chips (4 × 5 tiles with total sensitive area of 71 x 57 mm2 comprising 1.3 mega pixels). The measurements characterizing the detector performance were carried out in combination with high-quality neutron beamlines such as the cold neutron imaging instrument ICON at PSI, the high-flux instrument Neutrograph at ILL and the newly built thermal neutron imaging beamline at the Nuclear Physics Institute in Rez near Prague. At all these facilities, high-resolution high-contrast neutron radiography with the newly developed detector have been successfully applied for imaging of objects that were due to their size earlier with hybrid pixel technology difficult to image, for example, various composite materials (for aerospace industry), objects of cultural heritage, larger paleontological samples etc.

Neutron spectrometry measurements are widely performed for nuclear physics experiments and radiation protection purposes. A new Micro-Pattern Gaseous Detector (MPGD) for neutron spectrometry was designed, constructed and tested. It is composed by a neutron conversion board divided in six regions, each one dedicated to a different energy range. The read-out detector is a triple Gas Electron Multiplier (GEM) specifically conceived for this application and the neutron spectrum is measured by unfolding the counts from each region. The detection principle resembles the Bonner Sphere Spectrometer (BSS) but with planar geometry and a single instrument irradiation required. The geometry and response matrix of the spectrometer was simulated with the FLUKA code, covering an energy range from 10^-4 eV to 100 MeV. Tests were performed with radioactive sources in order to investigate the operation parameters of the device for maximum counting efficiency and photon signal elimination. The possibility of measuring neutron spectra was successfully explored with a ²⁴¹AmBe source at the Calibration Laboratory at CERN; further measurements are planned at the CERF facility at CERN.

During LHC Run 1, the Track Reconstruction algorithm for the ATLAS Trigger was based on a linear transformation of the Space Points, similar to a Hough-Transform. This method allows finding the tracks of a vertex in linear time but requires the positions of the interaction points beforehand. Critical for its physics performance is therefore an efficient algorithm to determine the vertices. Offline reconstruction methods can also gain heavily from an accurate and reliable vertex finding. Unfortunately, the vertex finding algorithm used in Run 1 has decreasing efficiency due to increasing noise levels with increasing pileup interactions. To validate the applicability of the original approach for increasing levels of pileup, a detailed study of possible Inner Detector event topologies, restricted on Space Points, was conducted. It determines the probability that a primary vertex is distinguishable from pileup interactions. The results of this study show the basic idea of the original approach to be applicable under the changed conditions as well. A vertex finding algorithm substantially improving on the algorithm used during Run 1 is presented in this work and has been implemented. This algorithm eliminates almost all noise, leaving a clear primary vertex signature.

One of the most important aspects in the development life-cycle of large Monte Carlo codes is the rigorous validation of the physics predictions and the comparison of calculations with experimental data. Geant4, a toolkit for the simulation of the transportation of particles in matter, is being regularly tested by the developers and by the users to verify the correctness of its results. The level of agreement with experimental data is being studied using dedicated test-suites created and maintained by the Geant4 developers. To complete this testing, in the recent years, a testing system has been put in place to automatically perform a series of technical tests to verify the correctness of the code. In this paper we describe new developments that allow to combine the two approaches. Given the expected high requirements in terms of CPU we have adapted this application to run on HPC resources. After discussing the application and its novel characteristics we will demonstrate its usefulness comparing with some experimental data. Finally we will discuss its prospects and extensibility.

Measurements of the neutrino mixing over the last decades established that the lepton flavor is not a concerved quantum number, which has greatly raised the importance of studying the lepton flavor violation in the charged lepton sector (CLFV). The Mu2e experiment at Fermilab searches for the µ-conversion on Al, which along with rare muon decays µ->e? and µ->eee is one of the most promising channels for CLFV observation. After three years of data taking, Mu2e is expected to reach the sensitivity level of R_µe = 6 × 10^-17 (@ 90% C.L.), improving the current limit on \convrate by four orders of magnitude. The Mu2e detector is composed of a tracker and an electromagnetic calorimeter. The 3.2-meter long tracker consists of 20 straw tube stations. Each station is made of four planes of D=5 mm straw tubes filled with the Ar/CO2. The tracker momentum resolution is better than 120 keV/c @ 105 MeV/c. The calorimeter consists of two disks, each one made of 930 BaF2 crystals. In addition to providing excellent particle identification capabilities and the fast online trigger, the calorimeter improves the track reconstruction capabilities of Mu2e. We present a calorimeter-seeded strack finding strategy which allows to increase the tracking acceptance by about 10%. Another issue discussed here is the technique for resolving the drift sign ambiguities. It becomes especially relevant, given the small diameter of the Mu2e straws. We present a technique of resolving the drift sign ambiguities significantly reducing the momentum resolution tails, of primary importance for the Mu2e physics reach.

Liquid scintillation counter (LSC) has been used as a very efficient technique for a quantitative measurement of radioactivity. The LSC has been the most powerful tool in the fields of low level environmental radioactivity monitoring and the detection of low energy beta decay events of radioactivity. In LSC the sample is dissolved in liquid scintillation cocktail in a sample vial. The LSC counts the number of flashes of scintillation lights and then quantify the nuclear decay in terms of activity. Due to the influence of quench that the sample solution absorbs part of nuclear decay energy and photons of scintillation lights escape detection. As a consequence, the observed count rate becomes less than that of actual energy. Moreover, the generated scintillation lights may be lost or escape during the optical trace to the photomultiplier detectors. Therefore the compensation of the count rate loss is essential to determine the sample’s activity. There are many techniques to determine the efficiency, however, it is known that those techniques lead different results especially in low energy beta decay radionuclides such as tritium. We previously reported on the development of a Geant4 based Monte Carlo simulation and validated the beta-ray scintillation spectra in LSC. The simulation takes into account radioactive decay, flashes of scintillation lights, and transportation of visible photons including reflection and refraction characteristics at material boundaries. This paper reports on the systematic analysis about the detection efficiencies of H3 and C14 samples in LSC, in terms of influences of quench levels and variation of system configurations.

Particle therapy system simulation framework, PTSIM, is a simulation framework based on Geant4 Monte Carlo simulation. It has been originally developed for particle radiotherapy to simulate dose distribution inside patient. PTSIM has provided a common platform to model proton and ion therapy facilities, allowing users who are not Geant4 experts to accurately and efficiently run Geant4 simulations with the pre-build configurations. Efforts on further development of PTSIM are still under way to include more functionality and improve the performance. In proton therapy, innovations of treatment machines such as a layer-stacking irradiation system and a pencil beam scanning irradiation system have been made for delivering more ideal dose distributions. In order to perform a specially optimized treatment for each patient, e.g. a tailor made proton therapy, there is a strong request to monitor the dose distribution inside patient by measurements besides the calculations. The dose monitoring is performed by reconstructing dose images by detecting prompt and annihilation gamma rays that are produced from radioisotopes in nuclear interactions with patient tissues. The PTSIM has an important roll to simulate the secondary isotope productions, its decay, and the signals in imaging devices in addition to delivered dose distributions. The results are used for optimizing detector configurations and mapping the reconstructed dose images to the delivered dose distribution. In this paper, we reports on the implementations of extending functions in PTSIM to medical imaging applications.

Fluoroscopic barium meal (BM) studies (an X ray examination of the esophagus, stomach, and duodenum) are widely used to observe digestive functions or to diagnose abnormalities such as gastroesophageal reflux disease (very common in children). Not only the medical exposure is a concerning, but also the occupational one, due to the fact that occupational workers (OW) stay in the examination room. Thus, the OW dosimetry and the irradiation characteristics knowledge are important parameters that need to be investigated, so that the radiological effects may be evaluated. The main objective of this work is to evaluate the scattered spectra by different pediatric phantoms (simulation patients subjected to BM procedures), that represent average ages, making possible to generate an energy correction factor to collected sign. To evaluate that, thermoluminescent dosimeters (TLD) were positioned over three areas in two OWs: eyes, thyroid and hands. The TLDs (LiF:Mg,Cu,P) were calibrated in the same fluoroscopy equipment when the procedures were performed, and therefore, the X-ray beam quality was equivalent to that used in the BM studies. However, the calibration was performed with the dosimeters under the primary beam. In this manner, the Geant4 toolkit was used to define the spectra that achieved TLDs and made possible to correct ESD. Without this information the doses would be calculated based on primary spectra. The present work was developed in five stages: (i) collection of validation experimental data, (ii) collection of TLD doses on OWs, (iii) validation of simulated data, (iv) evaluation of scattered spectra by different standard patient phantoms; (v) definition of scattered spectra that interact to each TLD. This is a work in progress, but preliminary results show that Geant4 is a good tool to these analysis. This methodology made possible to generate a correction factor to TLD sign collected.

Proton radiology and proton computed tomography are the new techniques being actively developed now to substitute X-ray computer tomography and nuclear magnetic resonance method in proton therapy. They deals with relatively thick targets like the human head or trunk where protons lose the major part of their energy but have enough to exit the target. The physical quantities important in proton imaging are proton exit energy, angle and coordinate. Nowadays many research groups are using Geant4 toolkit for development of the proton imaging devices. However the most of available publications about validation of the Geant4 models are or for thin absorbers, or for energy deposition of completely absorbed protons (Bragg Peak), but not for characteristic important in proton imaging. The objectives of this work is to validate different models available on Geant4 (version 9.6.p03) taking into account its accuracy and computational performance from the viewpoint of proton imaging. Considering the models available in Geant4 and applicable up to energy of 300 MeV the Physics Lists FTFP_BERT_EMY, FTF_BIC_EMY, QGSP_BERT_95_EMY, QGSP_BERT_EMY, QGSP_BIC_EMV and QGSP_BIC_EMY were implemented. In this study, the attention was concentrated on the distributions of exit energy, angle and lateral displacement, considering the monochromatic and monodirectional primary proton beam with kinetic energy from several MeV up to 300 MeV.

We develop on-stream energy-dispersive X-ray diffraction (EDXRD) mineral analysers for the minerals processing and mining industries. To optimise the design and performance of our systems, we have developed a computer code that facilitates the selection of the optimal design for a given material. Monte Carlo modelling was used to simulate the diffraction profiles produced by 28 125 EDXRD design geometries. From these profiles the diffraction peak resolution and count-rate efficiencies were calculated and stored in a database. Using this data, the performance of similar designs not modelled could be calculated, expanding the number of designs in the database to 1 723 392.
To facilitate the selection of the optimal design for a given measurement application, a code was developed to search the database and return the best design. The code was written in MATLAB and a graphical user interface (GUI) created developed. The GUI contains functions that allow the user to specify the exact requirements of the measurement application and to be specific in the way the database is searched. These functions include specification of 1) the material to be measured, 2) key diffraction lines, 3) source properties, 4) detector properties, 5) physical size limits for the instrument, 6) preferred or important design properties and 7) resolution limits. The code searches the database based on this input and returns the design that provides the best measurement performance. The advantages of the optimisation system were demonstrated by designing a potash ore analyser using the GUI. The measurement performance of the analyser was compared to that of our in-house laboratory EDXRD instrument by Monte Carlo modelling the diffraction spectra of 20 potash samples, containing the minerals halite, sylvite, quartz, anhydrite, gypsum, kaolinite and hematite, with both the laboratory and optimised analysers. The optimised system showed superior measurement performance over the laboratory system.

Ground testing for the flight software of the Alpha Magnetic Spectrometer (AMS) requires a virtual environment which provides abnormal signals and also responds to the controller's commands. We introduced the hardware-in-the-loop method but implemented the simulation in an innovative way that skips traditional mathematical modeling. A simulation database derived from the real-time flight data provides a normal or abnormal environment, and a dynamic configuration mechanism makes the virtual world respond to the real world. This time-saving method has been successfully applied in the ground testing system for AMS and the paper presents the methodology and its applications.

A stabilization concept based on a self-learning R-Tree index method is presented and demonstrated with measurements from a 1.5’’x1.5’’ cerium bromide detector. The concept uses a cognitive filter, a digital filter for nuclear signals that continuously updates itself to the current temperature by adjusting the filter components. The R-Tree combines the information from this cognitive filter together with (a) data about the temperature gradient, (b) the current load on the detector in terms of counts per second and (c) the current gain shift, which is determined from the spectrum. This technique consequently belongs to the so-called supervised learning algorithms, because the source is known in advance. The method is characterised by two operational phases. First a training in an industrial grade climate chamber and with selected strong radiation fields are conducted, which is a common procedure for producing spectroscopic equipment, building a base set of data points in the R-Tree. Second, the R-Tree learning is not stopped here. It continues during the whole instrument lifetime. Each time a manual calibration is launched with a known (pre-selected) source, all data for adding new training information is available and the R-Tree is updated. The instrument learns while being in the field. Tests with cerium bromide detector are shown for an academic prototype system and for a complete commercial radio-isotope identification device. Limits of the stabilization are determined.

The European X-ray Free Electron Laser is a high-intensity X-ray light source currently being constructed in Hamburg that will provide spatially coherent X-rays in the energy range between 0.25 keV — 25 keV. The machine will deliver 10 trains/s, consisting of up to 2700 pulses, with a 4.5 MHz repetition rate. The LPD, DSSC and AGIPD detectors are being developed to provide high dynamic range Megapixel imaging capabilities at the mentioned repetition rates. A consequence of these detectors’ characteristics is that they generate raw data volumes of up to 12.8 Gbyte/s. In addition, the detectors’ on-sensor memory-cell and multi-/non-linear gain architectures pose unique challenges in data correction and calibration, especially given the large number of calibration parameters, which are in the order of 10⁹. We present how these challenges are addressed for the AGIPD and LPD prototypes within XFEL’s control and analysis framework Karabo, which integrates access to hardware conditions, acquisition settings and distributed computing. Implementation is mainly in Python, using self-optimizing (py)CUDA code, numpy and iPython.parallel to achieve near-real time performance for calibration application.

The Bonner Sphere Spectrometer (BSS) system is a well-established technique for neutron dosimetry that involves detection of thermal neutrons within a range of hydrogenous moderators. BSS detectors are often used to perform neutron field surveys in order to determine the ambient dose equivalent H*(10) and estimate health risk to personnel. In 2002 Barlett et al [1] highlighted a potential limitation of existing neutron survey techniques being due to a lack of consideration to the direction of the field, which has consequently led to overly conservative estimates of dose in neutron fields. This study involves modelling a directional neutron spectrometer based on three position sensitive 3He tubes located along three perpendicular axes within a single moderating sphere of high density polyethylene for real time spectrometric monitoring of neutron fields. The spectrometer has relatively low gamma sensitivity and is able to detect thermal neutrons and fast neutrons up to energy of 15MeV. The 3He tubes are used to detect thermal and cold neutrons, with 90% detection efficiency in the range of (0.085-20.4) eV. The neutron response has been modelled using the Monte Carlo code Geant4. The applicability of the device has been investigated, relying on simulated exposures to reference field of AmBe source. [1] D. Bartlett, P.Drake, F.d'Errico, M.Luszik-Bhadra, M.Matzke, R.Tanner, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 476(1–2) (2002)

We have improved the simple-backprojection (SBP) algorithm to be used for the image reconstruction of the semiconductor Compton camera GREI by making it accurately consider the angular estimation error of the Compton scattering that can vary event by event. The good imaging performance of the GREI had already been demonstrated for both bio-medical application and distant gamma-ray source imaging with reconstructed images by SBP deconvolution image-reconstruction method. Our intention of addressing the issue of the SBP is to resolve the problem of artifacts appeared in the three-dimensional tomographic images taken by the opposed dual-head GREI system, due to the use of simplistic position-independent point-spread funtion. As a result of applying the newly implemented SBP algorithm, we were able to improve the point-spread function by reducing the high-frequency background noise. We expect that this improvement expands the application range of GREI by enabling rapid image reconstruction with much better image quality.

Monte Carlo (MC) simulations in physics are known to be highly compute intensive applications because they track the life of each simulated photon, which interacts multiple times with surrounding tissue, generating secondary particles. Therefore, there is great interest in accelerating MC simulations with technologies such as shared-memory multiprocessors, distributed-memory mutlicomputers and Graphics Processing Units (GPU). Independently of which parallel technology is used and what speed-up is achieved, all these parallelization efforts have one thing in common: they are introduced after the MC software has been designed and written, because parallel execution was never part of the design. This means the source code needs to be modified and refactored, which is not only time consuming but also highly error prone. In addition, the parallel technology is usually not part of the implementation language making it even more difficult to adapt the code to new execution requirements. In this paper, we present a parallel MC framework for particle tracking in shared-memory multiprocessors, where parallel execution is incorporated at the very first stages of design. Since the system is also object-oriented (OO), parallelism is realized with active objects, that is objects with their own threads of control. The system is written in a concurrent (parallel) OO language in which parallelism is part of the syntactic language definition. This last feature is highly relevant because it allows a direct mapping between class design and parallel objects without the need of using multi-threading libraries. To test the framework, super classes are specialized into a 3D slab bioluminescence simulation. In addition to unitary test cases, a complete bioluminescence simulation are carried out to verify the correctness of the code. Finally, execution time and speed-up are measured to asses computational performance.

MCNP6 was used to model an experimental setup consisting of NaI detector placed inside a simple shielded box; the enclosure was constructed from steel plates connected to an aluminum subframe. Two sets of simulations were performed and compared to experimental results; in the first set, the material comprising the shielding was initially modeled with all elemental and isotopic constituents, but gradually reduced to pure iron. In the second set of simulations, the enclosure was accurately modeled, e.g. aluminum frame, overlap of steel plates, etc. then simplified by steps to a single plate placed between source and detector. Simulated results show that reducing the material complexity resulted in a maximum overestimation of 0.2% in the effectiveness of the shielding, while a 3.7% overestimation occurred when simplifying the geometry to a single plate. The corresponding computation time decreased by a factor of 4.5 when run on the same system under identical conditions.

A two dimensional photon attenuation analytical transport model has been designed and validated in order to determine the optimal detection placement of scintillating gamma detectors. This analytical model is compared and contrasted against a full scattering, three-dimensional model in the Monte Carlo n-Particle (MCNP) simulation software suite. Our two-dimensional attenuation model is able to predict optimal detector locations with the same proficiency as the MCNP simulation in approximately 1/168th of the time using the same computing hardware and with comparable accuracy (14 hours versus 5 minutes). Since faster predictions are important in achieving useful methods for optimizing detector localization, the two-dimensional analytical model allows for significant rapid detector deployment in situations that require optimal hidden source detection with minimal resources.

Monte-Carlo radiation simulations calculate various particle tracking and particle interactions in radiation detectors, equipment, a human body and so on. Especially, human data obtained by a CT scanner has complex structure and large size generally. Therefore, particle tracking in human body has to be considered efficient calculation speed with suitable accuracy. In our research, an adaptive tetrahedral mesh is introduced for representing geometry of such a human body. Because the adaptive tetrahedral mesh has usually fewer cells than a hexahedral mesh such as an octree mesh. The number of cells affects the calculation speed because it is necessary to search cells in particle tracking. However, The cell search is a problem for the calculation speed. Therefore, a GPU-accelerated fast cell search algorithm for the adaptive tetrahedral mesh has been developing. The adaptive tetrahedral mesh generation is described. It has the GPU-accelerated fast search of cells in the tetrahedral mesh. The volume visualization software has been also developing for visualizing outcomes of a Monte Carlo radiation simulation, which uses the adaptive tetrahedral mesh in order to search cells for ray casting. It has functions to draw calculated physical quantities, trajectory lines, radiation equipment and volume data such as a patient structure scanned by using a CT scanner.

The Department of Homeland Security’s Domestic Nuclear Detection Office has funded a large scale simulation effort to quantify the detectability of special nuclear material (SNM). A previous study was performed to characterize the neutron signature of generic SNM sources, while this work focuses on the photon signatures. The simulations were performed for 265 different parameter variations of mass of SNM, shielding material, shielding thickness, and distance to detector. Receiver operating characteristic curves were chosen to quantify the photon detectability in reference to background. The background spectrum was taken from the most recently created background.dat file (release 4) that will be available with the next production release of MCNP6.1.2. The background spectra incorporate both cosmic and terrestrial produced photons as well as cosmic neutrons for (n,?) and (n,f) reactions. The background spectra are combined with the natural decay photons and spontaneous fission of the SNM isotopes to produce the total source definition. The photon signal is collected at a varied distance to a modeled NaI(Tl) detector. The work presented here is part of an ongoing effort to characterize the cost to detection benefit for SNM interdiction. Key Words: MCNP, ROC curves, SNM, HEU, gamma detection