Program Listings

Session Chair: Ivan Khodyuk, LBNL, United States; Angelo Dragone, SLAC National Accelerator Laboratory, United States

TRACE is a new detector based on silicon pad technology for detection of particles and light ions in fusion evaporation and direct nuclear reactions, whose identification relies on pulse shape analysis and requires sampling pulse windows of 1us at 200MHz with strong restrictions on power, area and connectivity. An analog memory ASIC named PLAS (PipeLined Asymmetric SCA) is presented that performs local triggering, sampling, zero suppression and serialization at the front-end. The circuit contains 64 independent input channels whose polarity and gain can be selected with an external resistor and programmable reference voltage, comparator thresholds and local trigger conditions. A novel analog memory architecture is presented that splits the typical Switched Capacitor Array (SCA) in two asymmetric stages connected with a switching matrix. The first stage has a 32-cell SCA per input that is continually sampling. The second one has 8 shared slots with 32- and 192-cell SCAs. When an input is triggered, a free slot in the second stage is assigned where posttrigger samples are acquired. Meanwhile, the 32 pretrigger samples are transferred to the 32-cell SCA in the second stage. As capture ends, the contents of the first stage have been copied and sampling resumes immediately with no dead time. Stored data are read serially and digitized remotely at 50 MHz in a frame format containing the samples and the digital trigger timestamp. The second stage is managed like a FIFO queue. The advantages of this architecture are the lack of readout-related dead time and area reduction by sharing storage resources between many inputs and expecting relatively low rates and multiplicities. The downsides are calibration complexity, different response for pre and posttrigger samples, and fixed pretrigger window sizes. The ASIC is designed in 0.18um CMOS technology. Samples are expected in December. Pre-layout simulations predict 100MHz bandwidth, 12 ENOB, 10mW per channel, and area below 15 mm2.

Abstract— The NA62 experiment at the CERN (Conseil Européen pour la Recherche Nucléaire) SPS (Super Proton Synchrotron) aims to measure the Branching Ratio of the very rare kaon decay K+ ? p+? ?-, collecting O (100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to the proposed measurement is represented by the K+? p+p-, decay. To suppress this background an efficient photon veto system is foreseen and it includes also the LKr (Liquid Krypton) Electromagnetic Calorimeter. The development of a high-performance as well as reliable digital data system addresses this issue providing the right bandwidth and efficiency to transmit experimental data to and from the counting room. This paper describes the LKr L0 trigger system, with particular emphasis in the LVDS digital data link used inside the system by means of COTS (Commercial Off-The-Shelf) chips operating in a high-energy physics environment (NA62 experimental area). The set-up implementation as well as the test protocol used to assess and qualify the digital data transmission system are the relevant part of the paper. The intensive tests performed on 70 TELDES are described and the excellent results accomplishing the NA62 experiment requirements are reported.

The high luminosity LHC upgrade will necessarily require a tracking trigger at level 1 to maintain manageable rates with sufficiently low thresholds. Dedicated hardware is needed to find tracks and make a trigger decision at the collision rate of 40 MHz. A road search algorithm for track finding based on seeds (tracklets) has been developed. The core steps of the algorithm, including seeding, track parameter calculation, and track fitting, have been implemented on commercially available FPGAs. We present results on the algorithm performance on a Virtex 7 chip, board-to-board communication, and a hardware model for a demonstrator system.

The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. The ATLAS Phase II upgrade will accommodate the detector and data acquisition system for the HL-LHC. In particular the Tile Hadronic Calorimeter (TileCal) will replace completely on- and off-detector electronics using a new read-out architecture. The digitized detector data will be transferred for every beam crossing to the PreProcessors (TilePPr) located in off-detector counting rooms with a total data bandwidth of 80 Tbps. The TilePPr implements increased pipeline memories and must provide preprocessed digital trigger information to Level 0/1 systems. The TilePPr module represents the link between the on-detector electronics and the overall ATLAS data acquisition system. It also implements the interface between the Detector Control System (DCS) and the on-detector electronics which is used to control and monitor the high voltage distribution system. The TilePPr is responsible for transmitting the commands to configure, control and monitor the on-detector readout electronics. We present the TileCal TilePPr requirements and plans for the Phase II upgrade of ATLAS as well as performance results of the first TilePPr prototype which has been built for the TileCal Demonstrator.

Pattern recognition associative memory (PRAM) devices are parallel processing engines which are used to tackle the complex combinatorics of track finding algorithms, particularly for silicon based tracking triggers. PRAM development has been mostly limited to the realm of ASICs, which often leads to lengthy and expensive design cycles. FPGAs allow for quick iterations, making them an ideal hardware platform for designing and evaluating new PRAM features before committing to silicon. The FPGA implementation of PRAMs will contain much less associative memory patterns than ASIC, however, it is highly desirable for early performance studies. For example, it can bring the system interface to maturity much sooner and minimize the ASIC design cycles. In this talk we present our FPGA-based PRAM designs and discuss how logic blocks which were originally developed for ASICs have been redesigned to take advantage of modern FPGA architectures. We also present our latest test mezzanine card design which supports both the ASIC and FPGA based PRAMs, and explain how the FPGA version of PRAMs will be used to help the ASIC development and implementation of PRAMs. This work is part of the overall program for Level-1 silicon-based tracking trigger generic R&D for high luminosity LHC.

It has become clear that the development of a L1 tracking trigger will be required for CMS to maintain physics acceptances for basic objects (leptons, photons, jets and MET) in the HL-LHC era and an associative memory-based track finding approach has been proposed to create this capability within CMS and deal with these high luminosities. Pattern Recognition by Associative Memory is a well-established approach that uses massive parallel processing to tackle the intrinsically complex combinatorics of track finding algorithms, avoiding the typical power law dependence of execution time on occupancy. VIPRAM (Vertically Integrated Pattern Recognition Associative Memory) takes advantage of the emerging technology of 3D integration to dramatically increase the number of patterns possible per square millimeter while increasing speed and minimizing power consumption. This talk presents the details of two VIPRAM implementations: 1) VIPRAM3D, a prototype chip that is necessarily 3D in its implementation and is meant to explore the benefits of 3D integration, and 2) VIPRAM_L1CMS, a high-speed prototype that is compatible (if necessary) with current bump-bonding technology and is meant to bring the Level1 system interface to fruition.

The LHCb experiment, that is presently taking data at CERN (European Center for Nuclear Research) Large Hadron Collider (LHC), aims at the study of CP violation in the B meson sector. Its key elements is the Muon detector, which allows triggering, and muon identification from inclusive b decays. The electronic system of the whole detector is very complex and its Muon detector Experiment Control System (ECS) allows monitoring and control of a number of Front-End boards in excess of 7000. The present system in charge of controlling Muon detector Front-End (FE) Electronics consists of 10 Crates of equipment; each crate contains two kinds of modules: a Pulse Distribution Module (PDM) and up to 20 Service Boards (SB) connected via a custom Backplane for a total amount of about 800 microcontrollers. LHCb upgrade is planned for 2018/19, which will allow the detector to exploit higher luminosity running. This upgrade will allow the experiment to accumulate more luminosity to allow measurements that are more precise. The main idea of the new architecture take advantage of the new CERN fast communication protocol GBT developed for radiation environment leaving unchanged the huge connectivity to the detector and the modularity of the system. The new chipset GBTx and GBT-SCA developed at CERN and the availability of more powerful computers allow designing a new system with fast link to the detector. In the new system, the control unit are moved from the apparatus to the computers in control room instead of the actual system where the low speed bus send high level commands to intelligent unit in the detector. The GBT system permits controls, monitoring and timing distribution using only two chips as building block all external control logic can be implemented in new high density radiation tolerant flash FPGA. This work show the hardware architecture of the each module and the whole system, analyze the aspect of the electronics design in hostile radiation environment.

Real time tracking is a key ingredient for online event selection at hadron colliders. The Silicon Vertex Tracker at the CDF experiment and the Fast Tracker (FTK) at ATLAS are two successful examples of the importance of dedicated hardware to reconstruct full events at hadron machines. We present the future evolution of this technology, for applications in the High Luminosity runs at the Large Hadron Collider (HL-LHC). Data processing speed is achieved with custom VLSI pattern recognition and linearised track fitting executed inside modern FPGAs, exploiting deep pipelining, extensive parallelism, and efficient use of available resources. In the current system, one large FPGA executed track fitting in full resolution inside low resolution candidate tracks found by a set of custom ASIC devices, called Associative Memories (AM chips). The FTK dual structure, based on the cooperation of VLSI AM and programmable FPGAs, is maintained, but we plan to increase the FPGA parallelism by associating one FPGA to each AM chip. Implementing the two devices in a single package would achieve further performance improvements, plus miniaturization and integration of the state of the art prototypes. We present the new architecture, the design of the FPGA logic performing all the complementary functions of the pattern matching inside the AM, the tests performed on hardware integrating the FPGA and the ASIC, the power consumption and performance running Monte Carlo events.

The design and performance of the ATLAS Inner Detector (ID) trigger algorithms running online on the high level trigger (HLT) processor farm with the early LHC Run 2 data are discussed. The HLT ID tracking algorithms are essential for nearly all physics signatures in ATLAS. The redesign of the ID trigger, which took place during the 2013-15 long shutdown, in order to satisfy the demands of the higher energy LHC Run 2 operation, is described. The detailed performance of the tracking algorithms with the early Run 2 data for the different trigger signatures is presented, including the detailed timing performance for the algorithms running on the redesigned single stage ATLAS HLT Farm. Comparison with the Run 1 strategy are made and demonstrate the superior performance of the strategy adopted for Run 2.

In the ATLAS experiment, the present muon Small Wheels will be replaced by the New Small Wheels (NSW). The NSW is a set of precision tracking and trigger detectors able to work at high rates with excellent, even at the L1 trigger, spatial and time resolution. The new detectors consist of the resistive micromegas and the small-strip Thin Gap Chambers (sTGC). To readout the high number of electronics channels and in order to survive in such a harsh environment new electronics must be fabricated. The L1DDC is an intermediate board that aggregates and transmits the L1 data from multiple front-end boards to a network called Front End LInk eXchange (FELIX). This is achieved using a high speed serializer/deserializer called GBTx developed at CERN. Furthermore, the L1DDC distributes Timing, Trigger and Control (TTC) data from the network to the front-end and the ADDC (Address real time Data Driver Card) boards. Generally, the L1DDC combines three distinct paths: TTC, Data Acquisition and Slow Control, into one bidirectional optical link at a rate of 4.8 Gbps.

After the Phase-II upgrade, planned for 2022, the average hit rate in the muon spectrometer will exceed the capabilities of the present readout electronics. The goal of the Phase II Muon Spectrometer upgrade is to maintain a level 1 trigger rate of no more than 100 kHz while keeping the pT threshold at 20 GeV/c. The rate will be reduced by tightening the pT threshold on the muon trigger through the addition of precision tracking information to the trigger. This requires the replacement of several components of the readout electronics. The two largest components to the upgrade of the upgrade are the replacement of the mezzanine cards responsible for sampling and time-stamping signals, and the central service module (CSM) boards which broadcasts timing and control signals to the mezzanine cards, and collects data from the mezzanines in response to a Level-1 trigger.

The present small wheel muon detector at ATLAS will be replaced with a New Small Wheel (NSW) detector composed of Micromegas and small-strip Thin Gap Chambers (sTGC) to handle the increase in data rates and harsh radiation environment expected at the LHC. The sTGC will be used for both trigger and precision tracking. Once a signal is detected, the sTGC front-end trigger logic will send out serialized track data on twinax cables to the signal packet router on the periphery of the NSW. The signal packet Router boards handle all incoming high-speed data and serve as a very fast switching-yard between incoming active TDS signals and a limited number of optoelectronic outputs. There are challenging requirements on the radiation tolerance, high-speed serial link and low fixed latency in FPGA. We will present the design and the test result of the router prototype we built.

The small-strip Thin-Gap Chambers (sTGC) will be used as both trigger and precision tracking muon detectors for the Phase-I upgrade of the ATLAS New Small Wheel (NSW) muon detector. A Trigger data serializer (TDS) ASIC is required to prepare trigger data for both sTGC pad and strip detectors, perform pad-strip matching, and serializer trigger data to the circuits on the rim the rim of the NSW detector. The large number of input channels (128 differential input channels), short time available to prepare and transmit trigger data (<100 ns), high speed output data rate (4.8 Gbps), harsh radiation environment (about 300 kRad), and low power consumption (<1 W) all impose great challenges for the design of this ASIC using the IBM 130 nm CMOS process. We present our design of the TDS ASIC and characterization of its performance from tests of the prototype we built.

The New Small Wheel (NSW) is an upgrade for enhanced triggering and reconstruction of muons in the forward region of the ATLAS detector at CERN's Large Hadron Collider.ï¿½ The large LV power demands necessitate a point-of-load architecture with on-detector power conversion.ï¿½ We present final results from an extensive campaign to test commercial power devices in radiation and magnetic fields, and describe an alternate solution based on a radiation-hard power conversion ASIC (the FEAST) produced by CERN microelectronics.ï¿½ We detail the challenges and solutions in integrating this device into the New Small Wheel, and outline the full resulting power system.

ATLAS is a general purpose particle physics experiment located on the LHC collider at CERN. The ATLAS Trigger system consists of two levels, the first level (L1) implemented in hardware and the High Level Trigger (HLT) implemented in software running on a farm of commodity CPU. The HLT reduces the trigger rate from the 100 kHz L1 accept rate to 1 kHz for recording requiring an average per-event processing time of ~250 ms for this task. The HLT selection is based on reconstructing tracks in the Inner Detector and Muon Spectrometer and clusters of energy deposited in the Calorimeter. Performing this reconstruction within the available HLT farm resources presents a significant challenge that will increase significantly after future LHC upgrades resulting in higher detector occupancies. General purpose Graphics Processor Units (GPGPU) are being evaluated for possible future inclusion in an upgraded HLT farm. We report on a demonstrator that has been developed consisting of GPGPU implementations of the Calorimeter clustering and Inner Detector and Muon tracking integrated within the HLT software framework. We give a brief overview of the algorithms implementation and present preliminary measurements comparing the performance of the algorithms implemented on GPU with the CPU versions.

This paper presents a custom 16-Channel, 12-Bit, 500 MHz ADC/Data Processing Module, designed for the KOTO Experiment at the Japan Proton Accelerator Research Complex (J-PARC). Few hundreds of this 6U VME board will receive signals from various detectors of the apparatus, and will be the digitizing modules in the Experiment’s Data Acquisition System (DAQ). In KOTO, the main ADC/DAQ system runs at a 125 MHz simultaneous sampling rate, provided by one low jitter 125 MHz system clock. The 500 MHz ADC Module receives this system clock and multiplies its frequency by four with an internal PLL. The 16 analog input pulses are passed to 8 dual channel ADC chips (ADS5407). After sampling, data are processed locally with two Field Programmable Gate Arrays (FPGA). The module is equipped with a pipeline up to 40us (20,480 samples) long, awaiting the system Level 1 trigger. After the trigger, data are packed and buffered for readout. The readout can be performed via the VME32/64 backplane, or via the two front panel QSFPs at rates of up to 48Gbps. Designed specifically for the KOTO Experiment, this module can also be used in many other Physics applications. The design and preliminary test results will be described.

The Pulsar IIb is a general purpose FPGA-based processor board designed for full mesh ATCA backplanes. This hardware was originally designed to support Level-1 silicon track trigger R&D projects at the LHC. Each ATCA board is required to support the Intelligent Platform Management Interface (IPMI) protocol, which is responsible for coordinating hot swap operations and for exchanging sensor data with the shelf manager. In this talk we discuss the development of the microcontroller software which supports the IPMI protocol as well as additional non-IPMI services used to remotely program the Pulsar IIb FPGA.

The trigger system of the ATLAS experiment at LHC will extend its rejection capabilities during operations in 2015-2018 by introducing the Fast TracKer system (FTK). FTK is a hardware based system capable of finding charged particle tracks by analyzing hits in silicon detectors at the rate of 105 events per second. The core of track reconstruction is performed into two pipelined steps. At first step the candidate tracks are found by matching combination of low resolution hits to predefined patterns; then they are used in the second step to seed a more precise track fitting algorithm. The key FTK component is an Associative Memory (AM) system that is used to perform pattern matching with high degree of parallelism. The AM system implementation, the AM Serial Link Processor (SLP), is based on a powerful network of 2Gb/s serial links to sustain a huge traffic of data. The design of the AM SLP is reported. The AM SLP consists of two types of boards: the Little Associative Memory Board (LAMB), a mezzanine where the AM chips are mounted, and the Associative Memory Board (AMB), a 9U VME motherboard which hosts four LAMB daughterboards. We also report on the performance of the prototypes produced and tested in the global FTK integration, an important milestone to be satisfied before the construction of the final FTK system.

The main purpose of the NA62 experiment at the CERN-SPS is to precisely measure the branching ratio of the ultra-rare decay K⁺ -> p⁺ ? ?bar with a signal to background ratio of 10:1. The expected branching ratio has been theoretically estimated to be of the order of 10^-10 and thus the measurement requires a high intensity kaon beam. In order to handle the intense unseparated flux of particles (~ 1 GHz), a high-performance and multi-level trigger and data acquisition system is needed.
The low level (L0) trigger processor represents a crucial component in reducing the event rate, estimated to be ~ 10 MHz for most of the sub-detectors which will form the trigger, by a factor 10 with a maximum admitted latency of 1 ms.
NA62 adopts a complex architecture to manage L0 information. In fact, trigger primitives, namely time, topology and physical quantities are digitized by a set of sub-detectors and then shipped to the trigger processor. Data are sent via Gigabit Ethernet links to an FPGA commercial development board that also routes selected triggers to the Timing Trigger and Control (TTC) system of the experiment for broadcasting. For the realization of the trigger selection, two different approaches were developed.
A first solution is fully based on a commercial development FPGA board, in which the whole logic for data selection is hardware programmed, while the second one joins an off-the-shelf PC to the same tool for greater flexibility in trigger programming.
Development, test results and compared performances during NA62 data taking will be presented.

Large array of macro-calorimeter detectors, operated at very low cryogenics temperatures, plays a crucial role for the search of rare events, such as Neutrinoless Double Beta Decay and Dark Matter. In experiments of this type the stability of the system is mandatory over many years of data taking, often in conflict with the intrinsic instabilities of the cryogenic setups. A solution to accomplish this requirement is to inject a voltage pulse across a heating resistor glued on each calorimeter absorber to develop a known calibrated heating power. For this purpose we designed a custom system able to generate a small and short voltage pulse across the heaters. This system is composed by different custom PCB each of them having multi-channel outputs. Each output can be completely remotely programmable from the acquisition system, in pulse width and amplitude, through an on-board Cortex-M3 microcontroller. Pulse amplitudes must be selectable, in order to handle each detector on its full dynamic range. Outputs can be connected to the heater in single-ended or differential configuration and the resolution of the output voltage is 12 bits over 5 V range (10 V in differential configuration). An additional 2 steps programmable voltage attenuator is added at each output. By using a 12-bit ADC and a 24-bit ADC is possible to perform on-board diagnostic, monitoring and self-check routines. The pulse amplitude thermal drift are compensated using a calibrated 8-bit, four channel trimmer. Each board is remotely controlled through an optically coupled CAN bus. In this contribution we present the solution adopted in the realization of a this very stable system.

Highly selective first level triggers are essential for the physics programme of the ATLAS experiment at the HL-LHC where the instantaneous luminosity will exceed the LHC Run 1 instantaneous luminosity by almost an order of magnitude. The ATLAS first level muon trigger rate is dominated by low momentum muons, selected due to the moderate momentum resolution of the resistive plate and thin gap trigger chambers. This limitation can be overcome by including the data of the precision muon drift tube (MDT) chambers in the first level trigger decision. This requires the implementation of a fast MDT read-out chain and a fast MDT track reconstruction. A hardware demonstrator which implements a multi-hit TDC with 4 ns precision for the fast read-out on an FPGA was successfully tested under HL-LHC operating conditions at CERN's Gamma Irradiation Facility. The test results showed that the data provided by the demonstrator can be processed with a fast track reconstruction algorithm on an ARM CPU within the 6 us latency of the first level ATLAS trigger anticipated for the HL-LHC.

The implementation of fully differential readout method for Silicon Photomultipliers (SiPM) is presented. The front-end circuit consists of preamplifier with fast shaper and Charge to Time Converter (QTC). The fast shaper generates unipolar pulse. The peaking time for single photoelectron is equal to 3.6ns and the FWHM is 3.8ns. The pulse width of the QTC depends on the number of photons. The gain of SiPM is compensated by moderating the bias voltage. The polarization voltage is adjusted indirectly by tuning the output common mode voltage (VOCM) of fully differential amplifier. The advantage of the algorithm is the possibility to set the bias of each SiPM in the array independently so they all could operate in similar conditions (have similar gain and dark count rate).

The ATLAS Liquid Argon (LAr) Calorimeters were designed and built to measure electromagnetic and hadronic energy in proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and at instantaneous luminosities up to 10^34 cm^-2s^-1. An LHC upgrade is planned to enhance the luminosities to 2-3 x 10^34 cm^-2 s^-1 and to deliver an integrated luminosity of about 300 fb^-1 during Run 3 from 2019 through 2021. In order to improve the identification performance for electrons, photons, taus, jets, missing energy at high background rejection rates, an improved spatial granularity of the trigger primitives has been proposed. Therefore, a new trigger readout system is being designed to digitize and process the signals with higher spatial granularity. A demonstrator system has been developed and installed on the ATLAS detector to evaluate the technical and performance aspects. Analog signal parameters including noise and cross-talk have been analyzed. The performance of the new readout system is being measured and experience will be gained for the development and construction of the full trigger readout system during the data taking run starting 2015. The performance of the demonstrator system in the data taking run will be presented. Based on the demonstrator system, the next generation of prototypes for the trigger readout system is being developed. In this talk, research and development of radiation tolerant custom ASICs for the final trigger readout system will be discussed.

Highly selective first level triggers are essential to exploit the full physics potential of the ATLAS experiment at the HL-LHC where the instantaneous luminosity will exceed the LHC Run 1 instantaneous luminosity by almost an order of magnitude. The ATLAS experiment plans to increase the rate of the first two trigger levels to 1 MHz at 6 µs latency and 400 kHz at 30 µs latency respectively. This requires new muon trigger electronics and the replacement of the read-out electronics of the muon trigger and precision MDT chambers. The replacement of the precision chamber read-out electronics will make it possible to include their data in the first level trigger decision and to increase the selectivity of the first level muon trigger. We use run-I LHC data to study different options how to use the MDT data and show that a substantial reduction of the first-level muon trigger rate to about 10~kHz is achievable.

One of the goals of the Cryogenic Magnetic Detector at Budker Institute of Nuclear Physics SB RAS (Novosibirsk, Russia) is a study of nucleons production in electron-positron collisions near threshold. The neutron-antineutron pair production events can be detected only by the calorimeters. In the barrel calorimeter the antineutron annihilation typically occurs by 5 ns or later after beams crossing. For identification of such events it is necessary to measure the time of flight of particles to the LXe-calorimeter with accuracy of about 3 ns. The LXe-calorimeter consists of 14 layers of ionization chambers with anode and cathode readout. The duration of charge collection to the anodes is about 4.5 mks, while the required accuracy of measuring of the signal arrival time is less than 1/1000 of that. Besides, the signal shapes differ substantially from event to event, so the signal arrival time is measured in two stages. At the first stage, the signal arrival time is determined with an accuracy of 1-2 discretization periods, and initial values of parameters for subsequent fitting procedure are calculated. At the second stage, the signal arrival time is determined with the required accuracy by means of fitting of the signal waveform with a template waveform. To implement that, a special electronics has been developed which performs waveform digitization and On - Line measurement of signals' arrival times and amplitudes.

The CMS experiment is currently undergoing upgrade of its trigger, including the Level-1 Muon Trigger. In the barrel-endcap transition region the variety of inputs, different data protocols and speeds, clocking type, complicated geometry and magnetic filed makes the triggering particularity challenging. The new Muon Trigger - Overlap Muon Track Finder (OMTF) is designed to work in this difficult region. It combines signals from RPC, DT and CSC detectors, process them and reconstructs muon trigger candidates. The OMTF uses the novelty approach to process data from those detectors in an uniform manner. The OMTF system is presented. The firmware solutions adapted for synchronisation, data transmission and algorithm implementation are emphasised.

NaNet is a modular design of a family of FPGA-based PCIe Network Interface Cards specialized for low-latency real-time operations. NaNet features a Network Interface module that implements RDMA-style communications both with the host (CPU) and the GPU accelerators memories (GPUDirect RDMA) relying on the services of a high performance PCIe Gen3 x8 core. NaNet I/O Interface is highly flexible and is designed for low and predictable communication latency: a dedicated stage manages the network stack protocol in the FPGA logic offloading the host operating system from this task and thus eliminating the associated process jitter effects. Between the two above mentioned modules, stand the data processing and switch modules: the first implements application-dependent processing on streams, e.g. performing compression algorithms, while the second routes data streams between the I/O channels and the Network Interface module. This general architecture has been specialized up to now into three configurations, namely NaNet-1, NaNet³ and NaNet-10 in order to meet the requirements of different experimental setups. NaNet-1 features a GbE channel plus three custom 34 Gbps serial channels and is implemented on the Altera Stratix IV FPGA Development Kit. NaNet³ is implemented on the Terasic DE5-NET Stratix V FPGA development board and supports four custom 2.5 Gbps deterministic latency optical channels. NaNet-10 features four 10GbE SFP+ ports and is also implemented on the Terasic DE5-NET board. We will provide performance results for the three NaNet implementations and describe their usage in the CERN NA62 and KM3NeT-IT underwater neutrino telescope experiments, showing that the architecture is very flexible and yet capable of matching the requirements of low-latency real-time applications with intensive I/O tasks involving the CPU and/or the GPU accelerators.

The NA62 experiment, aiming at measuring the branching ratio of the rare kaon decay K+ -> pi+ nu nubar at the CERN SPS, was installed and has taken first physics data in autumn 2014. We present the design, performance and operation during the 2015 high intensity data taking of the liquid krypton electromagnetic calorimer level 0 trigger for the photon veto in the 1-10 mrad decay region. The system is composed of 36 readout boards (TEL62), 108 mezzanines and 215 FPGAs. It identifies electromagnetic clusters, with an instantaneous hit rate up to 30 MHz, providing information on time, position and energy.

The Beijing Spectrometer (BESIII) is a general-purpose detector designed for high luminosity e+e- collisions in the t-charm energy region at the Beijing Electron Positron Collider (BEPCII). The time-of-fight (TOF) detector, devised through high time resolution detectors, is critical in particle identication for both nuclear and particle physics experiments.In order to further improve the particle identification capability of the Beijing Spectrometer (BESIII), we began to upgrade the current end-cap time-of-flight (ETOF) detector with multi-gap resistive plate chamber (MRPC). The plan is to get the resolution less than 80 picoseconds from current more than 110 picoseconds. The readout electronics for MRPC is based on NINO chip (amplifier and discriminator) and high performance TDC (HPTDC).The prototype has been tested and the result is very good. The time resolution (sigma) of ETOF system is 40 picoseconds (proton beam) and 45 picoseconds (pion beam). The efficiencies of three MRPC modules tested are better than 98% for both proton and pion beam.

The CMS detector is one of two general-purpose detectors at the CERN LHC. LHC will provide exceptional high instantaneous and integrated luminosities after second long shutdown. The forward region |?| = 1.5 of the CMS detector will face extremely high particle rates in 10’s of KHz/cm^2 and hence it will affect the momentum resolution and longevity of the muon detectors. To overcome these issues the CMS-GEM collaboration has proposed to install new large size rate capable Triple Gas Electron Multiplier (GEM) detectors in the forward region of CMS muon system. The first set of Triple GEM detectors will be installed in the GE1/1 region (1.5< |?| <2.2) of muon endcap during the long shutdown 2 of the LHC. Towards this goal, five full size CMS Triple GEM prototype chambers have been fabricated and put under the test beam at the CERN SPS test beam facility. The GEM detectors were operated with two gas mixtures: Ar:CO2 (70:30) and Ar:CO2:CF4 (40:15:45). There were two extensive data taking campaigns during 2014 where good quality data was collected under various detector and readout configurations. In this presentation, the performance of the detectors will be reported as a function of the abovementioned data taking yielding spatial resolution, tracking efficiency, cluster size and various other relevant parameters which have been studied and will be presented.

To improve the muon trigger efficiency of the high eta region of the CMS experiment and to cope with the expected luminosity increase in the second phase of the LHC, new RPC detectors using low-resistivity materials are proposed to equip part of the high-eta region. Several beam tests at DESY and CERN have shown that new detectors using low resistivity glass (of less than 1010 ?.cm) could stand particle rates of few kHz/cm2 in its single-gap version and few tens of KHz:cm2 in its multi-gap version. Test of several months at GIF has confirmed the robustness of such detectors and new tests in the new GIF++ facility are planned to complete the study. In parallel the excellent timing the RPC and MRPC could provide will be exploited by developing a new low-noise ASIC equipped with precise TDC device.

Precision calibrations of the ATLAS muon spectrometer Monitored Drift Tubes (MDT) is essential for full physics potential during LHC Run-2. We report on the production of chamber-specific time-to-space RT calibrations that are derived hourly from the cosmic ray tracks in a dedicated gas monitor chamber (GMC) sampling both MDT supply and return gas lines. The GMC produces idealized Universal RT functions expressed for a standard gas pressure, temperature and voltage. These functions are subsequently tuned to each of 1200 chambers in the ATLAS cavern using on-chamber temperature readout, and detailed corrections that account for mb variations in localized gas pressures. This system is in continuous operation (as it was for LHC Run-1) and generates, with minimal CPU overhead, a daily set of calibrations that accurately tracks ppm level variations in MDT gas composition, and thus enables the full Pt resolution of physics signatures with final state muons.

Mechanical precision is a key-aspect of the high-rate capable Micromegas detectors for the upgrade of the Small Wheels of the ATLAS muon spectrometer. 32 SM2 quadruplets will be built by four German institutes with cathodes and strip-anodes made of stable honeycomb sandwiches. To achieve a single plane resolution below 100 micro m the deviation from planarity of a single detector plane must not exceed 80 micro m over the whole active area and the parallelism of the readout strips has to be within 30 micro m for a single read-out plane of 3pcbs, as well as between all four planes of a quadruplet. Precision tooling is used for the correct positioning of readout pcbs and readout sandwich planes. A CCD based optical method allows for control od strip position with an accuracy better than 5 micro m. For quality control of the planarity of the sandwich planes a laser distance sensor combined with a coordinate measurement system has been developed. Deviation from planarity below 10 micro m can be easily resolved. We will present the challenging construction procedure to achieve this high level of precision as well as our alignment strategy. This includes the construction and commissioning of a 2.5 m² lightweight rigid structure, which has an overall planarity of 20 micro m RMS and the measurement of the blow up of outer planes of a quadruplet due to 2 mbar overpressure of the Ar:CO2 detector gas, the standard situation in ATLAS.

The instantaneous luminosity of the Large Hadron Collider at CERN will be increased up to a factor of five with respect to the design value by undergoing an extensive upgrade program over the coming decade. Such increase will allow the precise measurement of Higgs boson properties and extend the search for new physics phenomena beyond the Standard Model. The largest phase-1 upgrade project for the ATLAS Muon System is the replacement of the present first station in the forward regions with the so-called New Small Wheels (NSWs), to be installed during the LHC long shutdown in 2018/19. The NSWs consist of eight layers each of Micromegas and small-strip Thin Gap Chambers (sTGC), both providing trigger and tracking capabilities, for a total active surface of more than 2500 m². It represents the first system with such a large size based on Micro Pattern (Micromegas) and wire detectors (sTGC). The precision reconstruction of tracks requires a spatial resolution of about 100 ï¿½m, and the Level-1 trigger track segments have to be reconstructed with an angular resolution of approximately 1 mrad. The basic sTGC structure consists of a grid of gold-plated tungsten wires sandwiched between two resistive cathode planes at a small distance from the wire plane. The precision cathode plane has strips with a 3.2mm pitch for precision readout and the cathode plane on the other side has pads for triggering. The pads are used to produce a 3-out-of-4 coincidence to identify muon tracks in an sTGC quadruplet. A full size sTGC quadruplet has been constructed and equipped with the first prototype of dedicated front end electronics. The design of the sTGC, together with the construction tolerance and assembly challenge, will be described. The performance of the sTGC quadruplet has been studied at the Fermilab (May 2014) and CERN (October 2014) test beam facilities to study spatial resolution and trigger efficiencies. Results of these test beam campaigns will be presented.

The instantaneous luminosity of the Large Hadron Collider at CERN will be increased up to a factor of five with respect to the design value by undergoing an extensive upgrade program over the coming decade. The largest upgrade project for the ATLAS Muon System is the replacement of the present first station in the forward regions with the so-called New Small Wheels (NSWs), to be installed during the LHC long shutdown in 2018/19. Small-Strip Thin Gap Chambers (sTGC) detectors are one chosen technology to provide fast trigger and high precision muon tracking under the high luminosity LHC conditions. We study ageing effects of sTGC detectors with a gas mixture of 55% of CO2 and 45% of n-pentane. A sTGC detector was irradiated with beta-rays from a Sr-90 source. Three different gas flow rates were tested. We observed no deterioration on pulse height of the sTGC up to an accumulated charge of 2.5 C/cm. By October of this year, we plan to have collected 10 C/cm.

The emission of greenhouse gases is an important subject for the design of future particle detectors and the operation of the present experiments. The particle physics detector community has already demonstrated to be sensitive to this topic at the design level: indeed, most of the gas systems recirculate the mixture injected. Contributions from R134a, CF4 and SF6 dominate the overall emission in terms of CO2 equivalent. Presently, gas mixture re-circulation and recuperation of gases from the exhaust are the main strategies for reducing the environmental impact of particle detection activities. However, as long term prospective, also the use of less invasive gases should be investigated. The present contribution summarizes the plan for converting the remaining open systems to gas recirculation and the results obtained during operation of a large LHC detector system with recuperated CF4. During 2014 the open mode gas system of the Muon RPC trigger detector of the ALICE experiment has been successfully upgraded to gas recirculation. In parallel, studies are on-going for evaluation possible intervention on other experiments. A CF4 recuperation plant based on warm separation was developed in the past few years for a LHC-CSC detector system using Ar-CO2-CF4 mixture. About 70 m3 were recuperated during 2012; however, the recuperated gas was never used since the risk of affecting the detector performances during data taking was considered too high. The LHC-Long Shutdown 1 offered the opportunity to test the effect of using the recuperated gas. Gas mixture composition and detector performances were monitored all along the test with gas chromatograph, infrared analyser and dedicated detector monitoring. In many cases, also small R&D and laboratory activities are contributing significantly to the emission of greenhouse gases. A new simplified and flexible gas re-circulation system has been developed. Several gaseous particle detectors have been operated successfully using the new system at different gas system conditions.

The Resistive Plate Chamber (RPC) detectors are widely employed as muon trigger systems in three experiments at the Large Hadron Collider (LHC) thanks to their excellent time resolution. A gas mixture made of C2H2F4 (R134a), iC4H10 and SF6 is used for LHC RPCs operation in avalanche mode. Unfortunately R134a and SF6 have a Global Warming Potential (GWP) of 1430 and 23900 respectively, classifying them as greenhouse gases. Indeed the European Union will start to phase out refrigerants with GWP higher than 150 in the near future and the use of R134a for the large gas volume RPC systems will become critical in view of long term operation. The only possibility for containing the LHC RPC detector operational costs is to move towards alternative gases in the future. Two eco-friendly candidates have been identified for substitution of R134a: R1234yf and R1234ze with a GWP of 4 and 6, respectively. A dedicated experimental set-up has been implemented to study single-gap RPCs performance in terms of avalanche and streamer operation as well as to evaluate the quenching and electronegative capacities of the selected environmental friendly freons. Several new gas mixtures making use of only very low GWP gases have been tested. The first tests confirm that the replacement of R134a and SF6 with the new Freon is not possible and the addition of more reactive gases is necessary. RPCs have been successfully operated in streamer mode in a mixture of R1234yf, Ar and iC4H10. Nevertheless the operation in avalanche mode is less easily achievable with a simple addition of Ar to the new eco-friendly gases and a detailed research strategy has been addressed. Results on RPC operation in streamer and avalanche mode with several eco-friendly gas mixtures will be presented. In parallel an analysis campaign of compatibility of LHC gas system components with the new environmental friendly gases has been started making use of several gas analysis tools and mass spectrometer techniques.

Inner Trackers (IT) are key detectors in Particle Physics experiments; excellent spatial resolution, radiation transparency and hardness, and operability under high occupancies are main requirements. We aim to design, build and commission by 2017 a Cylindrical GEM (CGEM) detector candidate to be the new IT of the BESIII spectrometer, hosted on BEPC2 in IHEP, Beijing; BESIII data taking will last until at least 2020. The IT itself will represent an evolution w.r.t. the state of the art of GEM detectors, since the use of new kind of mechanical supports for the GEM foils will reduce the total radiation length of the detector and improve its tracking performance; an innovative design of the CGEM anode will allow for smaller capacitance and hence for bigger signals. The relatively strong BESIII magnetic field requires a new analogue readout; full custom front-end electronics, including a dedicated ASIC, will be designed and produced for optimal data collection. Prototype Beam Test results showing the measurement of the spatial resolution in a 1 Tesla magnetic field will be presented among with the mechanical design and simulations. In addition preliminary studies of uTPC mode readout will be presented, such development will improve the spatial resolution measurement in the magnetic field. The project has been recognised as a Significant Research Project within the Executive Programme for Scientific and Technological Cooperation between Italy and P.R.C. for the years 2013-2015, and more recently has been selected as one of the project funded by the European Commission within the call H2020-MSCA-RISE-2014.

Many experiments are currently using or proposing to use large area GEM foils in their detectors, which is creating a need for commercially available GEM foils. Currently CERN is the only main distributor of GEM foils, however with the growing interest in GEM technology keeping up with the increasing demand for GEMs will be difficult. Thus the commercialization of GEMs has been established by Tech-Etch Inc. of Plymouth, MA, USA using the single-mask technique, which is capable of producing GEM foils over a meter long. To date Tech-Etch has successfully manufactured 10 $\times$ 10 cm$^2$ and 40 $\times$ 40 cm$^2$ GEM foils. We will report on the electrical and geometrical properties, along with the inner and outer hole diameter size uniformity of these foils. Using our electrical and optical measurement setup, we also measured 10 $\times$ 10 cm$^2$ GEM foils produced by CERN for a direct comparison to the foils produced by Tech-Etch. Furthermore, Tech-Etch has now begun producing even larger GEMs of 50 $\times$ 50 cm$^2$, which are currently under active analysis. The Tech-Etch foils were found to have excellent electrical properties. The measured mean optical properties were found to reflect the desired parameters and are consistent with those measured in double-mask GEM foils, and show good hole diameter uniformity over the active area. These foils are well suited for future applications in nuclear and particle physics where large area tracking devices are needed.

The Compact Muon Solenoid (CMS) detector installed at the CERN Large Hadron Collider (LHC) has an extensive muon system which provides information simultaneously for identification, track reconstruction and triggering of muons. As a consequence of the extreme particle rate and high integrated charge, the essentiality to upgrade the LHC has given rise to the High Luminosity phase of the LHC (HL-LHC) project so that the CMS muon system will be upgraded with superior technological challenges. The CMS GEM collaboration offers a solution to equip the high-eta region of the muon system for Phase 2 (after the year 2017) with large-area triple-layer Gas Electron Multiplier (GEM) detectors, since GEMs have the ability to provide robust and redundant tracking and triggering functions with an excellent spatial resolution of order 100 micron and a high particle rate capability, with a close to 100% detection efficiency. In this contribution, the present status of the triple-GEM project will be reviewed, and the significant achievements from the start of the R&D in 2009 will be emphasized. Fundamental design of the triple-GEM detectors proposed for installation in different stations of the CMS muon system will be described along with the incorporated front-end electronics, data-acquisition system and the results from the detector tests.

Large size Micro Pattern Gaseous Detectors (MPGDs) are being proposed as the tracking devices of future spectrometers of the 12 GeV upgrade of the Continuous Electron Beam Accelerator Facility (CEBAF) at Thomas Jefferson National Laboratory (JLab) as well as the future Electron Ion Collider (EIC). We report on the R&D effort at the University of Virginia on GEM (Gas Electron Multiplier) detectors developed for the high luminosity experiments in Hall A and B at Jefferson Lab as well as the Forward Tracker for EIC. We describe the performance of two different large GEM prototypes from the test beam campaign at the Fermilab Test Beam Facility (FTBF). Our studies emphasize on spatial resolution of trapezoidal GEM with two- dimensional stereo angle (U-V) strips readout board built as pre-R&D prototype for SoLID and EIC. A perspective on a new construction technique of large area triple GEM is introduced and preliminary results of the largest GEM chamber, built for the proton radius experiment (pRad) in Hall B, are presented. Finally, we discuss the plans for the future R&D with a focus on minimizing even further the chamber radiation length in order to limit the high rate background induced by the detector itself when operating in a high rate and high background dominated environment of the 12 GeV era at JLab.

In this work we present the assembly and fisrt measurements on a High Pressure Gas Scintillation Proportional Counter envisaging a Compton Camera for nuclear medical imaging [1]. Despite the success of the Anger Camera in Nuclear Medical Imaging this device stills presenting some limitations: The use of photomultipliers (PMT) arrays leads to a high cost and fair position resolution. Also, the need of collimator limits the number of photons that reaches the crystals, leading to the increase of the dose delivered to the patient [2]. By using the so-called “electronic collimation”, I.e, a Compton Camera, it is possible to obtain the direction of the incoming photon avoiding the use of the collimator and thus, probably, reducing the dose to the patient[3]. Moreover, the Compton cross-section becomes dominant when the cross section for the photoelectric absorption decreases, triggering the possibility to use new radioisotopes with low detection on the traditional Anger Camera.[4]. Recently a Gaseous Compton Camera based on a High Pressure Gas Proportional Scintillation Counter and readout by a low cost and large area position sensitive gaseous photomultiplier (GPM)has been proposed[1]. The concept, setup, assembly and simulation results on the detector performance will be presented. Characterizations of the GSPC, namely the number of produced photons according to the gas, pressure and electric fields, by using a traditional PMT and the GPM will be presented. Imaging of the detector operated with the photoelectric effect will be also presented.

Fast scintillation detectors based on Lanthanum Bromide (LaBr3) crystals are nowadays commonly used in nuclear physics experiments, mainly to estimate energy and time information of ?-ray interactions. The Milano group is involved in the development and use of two scintillator arrays: i) a 10 large volume (3.5”x8”) detector array of pure LaBr3 (HECTOR+) and ii) a ?-calorimeter based on tens of LaBr3-NaI phoswich detectors (PARIS). A dedicated 16 channel NIM analog module handling these photomultipliers detectors signals has been developed in order to satisfy the experimental requests of both detector arrays. Each channel of the module is composed of three sections providing energy and time information. Section (1) provides a shaped signals proportional to the total energy of the ? ray (range 0-40 MeV). In case of pure LaBr3 detectors, section (2) provides another shaped energy signals (range 0-10 MeV) for dual range experimental requirements. For phoswich detectors, section (2) provides a shaped signal with amplitude proportional to the fast component of the signal; the analysis of the two dimensional spectrum (fast versus total) allows to disentangle the interactions in different part of the detector (LaBr3-NaI). Sections (3) is the constant fraction discriminator (CFD) that provides the time information. Slow control of the module parameters like gain, CFD thresholds, width of logic signals, etc. is allowed through a RS485 serial line.

Because the large nonlinearity errors exist in the current tapped-delay line style field programmable gate array (FPGA)-based time-to-digital converters (TDC), the bin-by-bin calibration technique has to be resorted to gain a high measurement resolution, which potentially increases the TDC design complexity, and limits the system performance. This paper proposes a new method reorganizing the original delay elements in FPGA to minimize the nonlinearity errors, so that the TDC could achieve a high time resolution without the aid of bin-by-bin calibration. Using a Kintex-7 Xilinx FPGA, the proposed TDC could achieve approximately 15 ps root-mean-square (RMS) time resolution by dual-channel measurement of time-intervals over the range of operating temperature, which is equivalent to the one using the on-line bin-by-bin calibration. The new design method is straightforward and resource-saving, thus the multi-channel capability of FPGA can be significantly improved.

Since few years, our group develops a family of ASICs for Space applications, named IDeF-X standing for Imaging Detector Front-end. IDeF-X BD is a new member of the family. It is a 32-channel analog front-end designed for spectro-imaging devices with self-triggering capability. It has been optimized for the readout of low capacitor (few pF) and low leakage current (<2nA) Silicon detectors. It is the readout ASIC of the silicon semiconductor diode detectors (SSDDs) in the STEP instrument aboard the Solar Obiter ESA mission. The architecture of the analog channel includes a Charge Sensitive Amplifier with a continuous reset system, a Pole-Zero cancellation stage, a variable shaping time fourth order low pass filter made of two Sallen & Key filters, an input polarity selector, a peak detector, and a discriminator with its own 6 bits threshold DAC. The power consumption is 3,3 mW per channel and the noise floor is 66 electrons rms. The chip is tolerant to a total ionizing dose (TID) of 300 krad and thanks to our Single Event Latchup hardened library should be SEL tolerant. The dynamic range of the chip of 11 fC (250 keV Si) and its ability to readout both polarities of signal make it usable for hard X-ray spectroscopy with SSDDs, Double Sided Silicon Strip Detectors (DSSSDs) but also with Cd(Zn)Te detectors. In the paper we will detail the performances of the chip including the linearity, the crosstalk between channels, but also the sensitivity of the chip to Single Event Latchup. Finally, the circuit will be evaluated by spectroscopy measurements performed with SSDDs.

Data Multiplexing has always been an attractive method for reducing the cost and complexity of the systems. In SiPM-based scanners with large increase of the number of channels multiplexing techniques can be very desirable. This paper presents an all on-chip method for integration and hold plus multiplexing of any number of channels for position and energy generation in this type of scanners. Compared to the time-over-threshold (TOT) technique, the proposed structure has improved timing and linear positioning and energy read-out for wide range of input current levels. In this work an 8-channel multiplexing structure has been designed and simulated in a 0.35µm SiGe process.

The Vertically Integrated Pattern Recognition Associative Memory, known as VIPRAM, was proposed as an aggressive R&D project at Fermilab to address the fast pattern recognition challenges for tracking trigger at the high luminosity Large Hadron Collider (LHC). Emerging 3D vertical integration technology allows VIPRAM to have higher pattern density and reduced interconnect latency and parasitic capacitance. This R&D project follows a staged strategy. As the first step, a 2D prototype demonstrator chip (protoVIPRAM00) has been implemented in conventional VLSI for the purpose of design verification while the basic building blocks are 3D compatible. The first 2D prototype has been successfully tested and its performance extensively studied in 2014 (see another abstract at this conference), and the basic building blocks are now ready for 3D stacking. Due to increase in thermal resistance and decrease in cooling efficiency, power and thermal issues should be studied carefully at early stage before actual 3D stacking. In this paper, we present a complete power and thermal characterization of the 2D demonstrator chip protoVIPRAM00 for the purpose of extrapolating power and thermal behavior to 3D VIPRAM chip. First, the power behavior is characterized by detailed transistor level circuit simulations on all voltage sources with representative input data types. Actual power measurements are performed over both pseudo-realistic test cases obtained from High Luminosity Large Hadron Collider (HL-LHC) simulation and stress test cases designed to push the chip’s operational boundaries. Second, the thermal behavior is characterized through modeling and simulation using state-of-the-art commercial thermal simulator FloTHERM V9.2. Pseudo-realistic power set obtained from power characterization is used in our thermal model. Due to the uniform and repetitive nature of the VIPRAM associative memory design, VIPRAM is a good initial testing ground to develop and calibrate power thermal models for future 3D designs in general.

A new n-MOSFET layout which combines a DGA n-MOSFET and a guard drain is both TID and SEE radiation-tolerant. The proposed n-MOSFET layout consists of a p+ and a p-active layer on the source-to-drain sidewall to prevent the development of a leakage path between the source and the drain, a dummy gate on the side drain/source to avoid the development of a leakage path between two MOSFETs, and a guard drain on the side dummy gate to reduce the SEE effect. The proposed n-MOSFET layout is an approach method of layout modify. It is advantageous that the proposed n-MOSFET can easily be used to design an analog or digital circuit with TID and SEE radiation-tolerance using a commercial bulk silicon substrate process. The proposed n-MOSFET layout is eliminated all radiation-induced leakage current paths and reduced to 35.36% of SEE pulse in comparison with the conventional n-MOSFET. The simulation results demonstrated that the proposed n-MOSFET structure on the bulk silicon substrate performed well, as expected, even when the fixed charge density was increased and energetic protons were injected. These results confirm that the proposed n-MOSFET on the bulk silicon substrate is radiation-tolerant.

The SAR ADC using Dummy Gate-Assisted (DGA) n-MOSFET is presented with a custom-designed capacitor. The prototype chip was implemented in a commercial 0.35um CMOS process and its radiation tolerance was proved by radiation exposure experiment.

For more than two decades, the Digital Trapezoidal Shaping (DTS) has been successfully incorporating in the various nuclear spectroscopy systems. The DTS filter [3] outputs a signal with trapezoidal shape. It can be implemented by breaking DTS filter into a cascade of filters and by using corresponding recursive relations as proposed in the references [1] and [2]. In this work we have derived a new DTS cascade of filters and corresponding set of the recursive relations and shown how to implement them in a FPGA by using optimal arithmetic precision. Since the first stage in the proposed cascade is an impulse deconvoluver, we have found that is feasible to remove impulses which would cause pile up at the output of the DTS filter. The impulses removed from one cascade can be processed by adding a new cascade operating in parallel, hence virtually eliminating pile-up. The proposed impulse separation algorithm was implemented and successfully tested on Xilinx Zynq®-7000 All Programmable System-on-Chip. References: [1] V. T. Jordanov at al. “Digital Techniques for Real Time Pulse Shaping in Radiation Measurements”, Nuclear Instruments and Methods in Physics Research A 353(1994)261-264 [2] A. Georgiev and W. Gast, “Digital Pulse Processing in High Resolution, High Throughput Gamma Ray Spectroscopy”, IEEE Vol 40 No [4], 1993 [3] C. Imperiale, A. Imperiale, “On nuclear spectrometry pulses digital shaping and processing”, Measurement 30 (2001) 49 –73

We present a low-noise Charge-Sensitive Preamplifier for HPGe detectors able to swiftly recover from saturation, featuring an auxiliary output signal used for high-resolution pulse-height spectroscopy of the over-range signals. Using the auxiliary output for analyzing the signals larger than ~15 MeV (mostly charged particles and heavy ions) and the principal preamplifier output for analyzing all other signals (ionizing radiations and charged particles) a wide overall spectroscopic energy range of 5keV to 180MeV is obtained. A single Pole-Zero adjustment serves both the principal preamplifier channel as well as the auxiliary output channel. The energy resolution of the auxiliary channel is better than 0.1% typically. The Equivalent Noise Charge of the preamplifier is 115 electrons r.m.s., i.e. ~0.8 keV fwhm, using a BF862 as input transistor operated at room temperature while simulating the detector with a capacitance of 22 pF.

In this work we present an innovative all integrated solution, which incorporates on the same chip both a low-noise low-power charge-sensitive preamplifier and an integrated range booster with second-order effect compensation. The booster is based on a particular Time-to-Amplitude Converter which generates analog signals whose amplitude is directly proportional to the energy of the events that caused saturation (ions, energetic charged particles). In this way a dynamic range from a few keV to more than 800 MeV is obtained.

This work presents the design and characterization of a low-power 16-channel charge sensitive amplifier (CSA) in 130nm CMOS for a UV imaging detector for space applications. The UV detector consists of a 2-D cross strip anode array behind a micro channel plate (MCP), having anodes connected to a CSA. The CSAv3 amplifier is composed of a charge sensitive amplifier, pole-zero cancellation circuit, a programmable shaping amplifier and an output stage buffer with polarity selection. The SPICE simulations carried out on the completed design provide noise figures on the order of 580 electrons with an output signal full-width half-maximum (FWHM) value of 50ns for event rates up to 10MHz.

This paper presents design and preliminary performance of a mixed-signal front-end electronics dedicated to CZT detectors. It is implemented by a full-customized readout application-specific integrated circuit (ASIC) with a post digital pulse shaping algorithm in FPGA. In this scheme, the analog front-end consists of a preamplifier using split-let topology followed by a variable gain amplifier. A multiple-point sampling ramp ADC is integrated to digitize the amplified pulse voltage signals into multiple point sampling data. The digital CR-RCn shaping and digital trapezoidal shaping algorithms are implemented in a FPGA. Meanwhile, the triggers are digitized by a time-to-digital converter in the time channel of FPGA. A prototype ASIC is implemented in CMOS 0.35 μm mixed-signal process. The preliminary results have been obtained. The detection range of the gamma ray is from 11.2 keV to 550 keV. The linearity of the output voltage is less than 1 %. The gain of the readout channel is 40.2 V/pC. The test results show that the proposed front-end electronics is appropriable for PET imaging applications.

This paper presents the development of a 16 channel GSPS digitizer on chip named HalfGRAPH2. The ASIC chip enables the construction of a compact readout system for a space application single photon sensitive UV imaging detector. Each input channel of the chip, has a sampling array composed of switched capacitors with a common sampling timebase. An additional analog array of capacitors serves as an analog memory about 8us deep. The Wilkinson ADC converters built into the chip, digitize the sampled signal stored in the array. In order to increase the data throughput, the chip enables samples conversion and transmission simultaneously. The digitized data are transmitted over 8 high speed low-voltage differential signaling (LVDS) pairs via serial communication. The chip is built in 0.250um TSMC technology. We present the chip architecture and its evaluation.

This paper presents a 12-bit 2MS/s pipelined successive approximation register (SAR) analog-to-digital converter (ADC) for CZT-based imaging system. The proposed ADC pipelines a first stage 6-bit Multiplying Digital Analog Converter (MDAC) with a second stage 8-bit split-capacitor SAR ADC which considerably reduce the power dissipation compared with conventional pipelined ADCs. To improve pipelined SAR ADC’s radiation tolerance, a full-customized digital standard cell library is constructed and annular gate devices are used to implement the layout of NMOS transistors. Meanwhile, the P+ guard ring and N+ guard ring are added in each NMOS and PMOS transistors and the distance between PMOS and NMOS transistors is enlarged. The proposed ADC will be fabricated in CMOS 0.18 µm mixed-signal 1.8V/3.3V process. The ADC occupies an area of 0.71 mm2 and dissipates 15 mW. The figure of merit (FOM) is 3.66pJ/conversion-step.

The latest experimental results of the multichannel CSP ASIC for TRACE detector are shown. The device, submitted to the foundry in the middle of 2014 and received at the end of the same year has been installed on a dedicated pcb and tested using a pulser. The device features four channels specifically designed for hole signals and one channel for electron signals. The power consumption is around 10 mW per channel as required by the specifications of TRACE. The main design goals are low noise and fast rise time. With proper shaping of the signals this device is capable of producing energy spectra with resolution of approximatively 1keV. The rise time of the leading edge of the signals is fast enough to perform pulse-shape analysis of the waveforms. The key feature of this device is the possibility to switch some internal components as desired through an I2C bus. In this way some critical parameters, such as bandwidth and gain of the preamplifier, can be adjusted and optimized according to experimental needs.

In the ATLAS Muon Spectrometer, Monitored Drift Tube (MDT) chambers and sMDT chambers with half of the tube diameter of the MDTs are used for precision muon track reconstruction. The sMDT chambers are designed for operation at high counting rates due to neutron and gamma background irradiation expected for the HL-LHC and future hadron colliders. The existing MDT read-out electronics uses bipolar signal shaping which causes an undershoot of opposite polarity and same charge after a signal pulse. At high counting rates and short electronics dead time used for the sMDTs, signal pulses pile up on the undershoot of preceding background pulses leading to a reduction of the signal amplitude and a jitter in the drift time measurement and, therefore, to a degradation of drift tube efficiency and spatial resolution. In order to further increase the rate capability of sMDT tubes, baseline restoration can be used in the read-out electronics to suppress the pile-up effects. A discrete bipolar shaping circuit with baseline restoration has been developed and used for reading out sMDT tubes under irradiation with a 24 MBq ⁹⁰Sr source. The measurements results show a substantial improvement of the performance of the sMDT tubes at high counting rates.

A novel digital imaging system using silicon-photomultiplier (SiPM) sensors is currently under development at DESY, Hamburg, for applications in high energy physics and photon science. The system is based on a thinned SiPM-sensor chip from MPG-HLL, Munich. The final readout chip will comprise a 32-by-32 pixel matrix with 50-µm pitch and will be realized in IBM’s 130-nm CMOS technology. It provides active quenching and recharging, fast and combinatorial trigger, time-to-digital converter, and fast readout of the pixel pattern at MHz-frame rates. A first prototype ASIC with 16-by-16 pixel matrix was designed including corresponding pixel electronics, fast trigger and single-row combinatorial trigger. The sensor-less operation is described and first measurements are presented. The maximal power consumption amounts to ˜15 µW per pixel at 1.2-V and 4 µW per pixel at 3.3-V supply voltage, respectively.

An 8-bit 5-MS/s Wilkinson-type analog-to-digital converter (ADC) cell has been designed for parallel in-pixel digitization in a 64-by-64 pixel readout ASIC. It is designed and fabricated in IBM’s 130-nm CMOS process and has a size of 14 x 15 mm². The ASIC is intended for the DEPFET Sensor with Signal Compression (DSSC) mega-pixel camera currently being developed for future applications at the European XFEL facility. First measurements of the 4096 ADCs working simultaneously at 4.5-MHz frame rate are presented here. The ASIC is tested in power-cycling mode with a 600-µs long on state and a repetition of 10 Hz adapted to the future bunch scheme of XFEL. All 4096 ADCs are working. Their maximum INL is better than ±0.5 LSB for 98 % of the pixels, their mean DNL is below 0.5 LSB. The input-referred noise voltage is <12 % of an LSB. One ADC consumes a power of 150 µW at 1.2 V power supply. An area of 0.012 mm² is required per ADC.

This work is concerned with the experimental characterization of a Charge Sensitive Amplifier featuring dynamic signal compression, fast recovery time, low noise and reduced area occupancy. The device takes advantage of the non-linear features of an inversion-mode MOS capacitor to fit a wide input dynamic range into the available output swing. It can be operated in synchronous mode at high frame rates, of the order of few MHz, thanks to a wide bandwidth, an improved output stage and a fast reset network. The reduced area occupancy makes the amplifier suitable to its integration in a 100x100 um^2 pixel area. All these features make the device a good candidate for applications where a fast front-end with a non-linear response is required, such as in imaging instrumentation for Free Electron Laser experiments. The aim of the paper is to show the experimental results coming from the characterization of the first prototype of the circuit which has been designed in a 65 nm CMOS technology within the PixFEL Project funded by the INFN, Italy.

Bootstrap readout topologies for analog-SiPM (aSiPM) with large terminal capacitance in TOF PET application are discussed in this paper. The main purpose of this work is to improve the signal integrity of the “critical paths” – scintillation signal from the PET detector photosensors to the analog frontend electronics. From previous “voltage amplifier” configurations to more popular “current amplifier” and “transimpedance amplifier” readout nowadays, achieving low input impedance is one of the main design goals. The bootstrapping readout method which we are focusing on is to improve PET detector response time by means of reducing the time-constant t=|Z|·C from both aspects: lower impedance Z: shunt-bootstrapping read out aSiPM from both anode and cathode in the “close loop” high bandwidth transimpedance amplifier configuration; lower “equivalent” capacitance C: reducing pulse “swing” amplitude across aSiPM anode and cathode by the shunt bootstrapping, and speedup capacitor charge/discharge through the negative-feedback shunt differential amplifier. We also presented our previous research works including “decompensated TIA” and “lead-lag compensation” for aSiPM readout. The “tri-exponential” scintillation pulse model is discussed here as an analytical tool for theoretical analysis. Then we analyzed the stability aspect of current-feedback and voltage-feedback amplifier in transimpedance (TIA) configuration as they are crucial for our “shunt bootstrapping” design. In addition, the frequency-oriented “fast-slow” pulse splitter design is discussed. It is the building-block successive the bootstrapping readout in the aSiPM readout signal chain. The design goals are to improve the “high frequency components” noise-to-slope ratio (NSR) from PET timing aspect, and the signal-to-noise ratio (SNR) in the “low frequency components” in PET energy and event-positioning aspect. We planned to complete the development and present the performance in the upcoming conference

We present the method and results of testing of 20 wafers of the UFXC chip designed and fabricated in the TSMC CMOS 130nm process. The integrated circuit is a hybrid pixel detector readout working in single photon counting mode. It has the dimensions of 2 cm x 1 cm while single pixel size is 75 um x 75 um. A single wafer consists of 120 dies each of which should be tested before further processing (bumping and flip-chip bonding). Our testing method allows for high-speed verification of the digital blocs functionality as well as the analog blocks quality characterization.

The European XFEL is an extremely brilliant Free Electron Laser Source with a very demanding pulse structure: Trains of 2700 X-Ray pulses are repeated at 10Hz. The pulses inside the train are spaced by 220ns and contain up to 10¹² 12keV photons each, while being =100fs in length. AGIPD (Adaptive Gain Integrating Pixel Detector) is a hybrid 1M-pixel detector developed by DESY, PSI, the Universities of Bonn and Hamburg to cope with these properties. Thus the readout ASIC has to provide not only single photon sensitivity and a dynamic range up to >10⁴ photons/pixel in the same image but also a memory for as many images of a pulse train as possible for delayed readout prior to the next train. The AGIPD 1.0 ASIC uses a 130nm CMOS technology and radiation tolerant techniques to withstand the radiation damage incurred by the high impinging photon flux. Each ASIC contains 64x64 pixels of 200µmx200µm. The circuit of each pixel contains a charge sensitive preamplifier with threefold switchable gain, a discriminator for an adaptive gain selection, and a correlated double sampling (CDS) stage to remove reset and low-frequency noise components. The output of the CDS, as well as the selected gain is sampled in a capacitor based analogue memory for 352 samples, which occupies about 80% of a pixel’s area. For readout each pixel features a charge sensitive buffer. A command based interface and control circuit provides random access to the memory and controls the row-wise readout of the data via multiplexers to four differential analogue ports. The AGIPD 1.0 full scale ASIC has been received back from foundry in fall of 2013. Since then it has been extensively characterised also with a sensor as a single chip and in 2x8-chip modules for the AGIPD 1M detector. We will present the design of the AGIPD 1.0 ASIC along with supporting results, also from beam tests at PETRA III and APS, and show changes envisioned for a planned AGIPD 1.1 ASIC upgrade.

We present the design and simulation of a readout and digitization ASIC for radiation detectors using modern Silicon Photomultipliers. The circuit is designed in standard CMOS 110 nm technology, has 64 independent channels and is optimized for time-of-flight measurement in PET or other applications. The chip has quad-buffered TDCs and charge integration ADCs in each channel, with linear response in the range 0-1500 pC and 600 kHz maximum event rate per channel. Simulation results show that for an impulse charge of 200 fC the circuit has 25 dB SNR, 93 ps r.m.s. time resolution, and 5 mW power consumption.

Positron Emission Tomography is widely used diagnosis equipment for metabolic diseases. Generally, PET system is consisted of sensors, preamps, position decoding circuits and a data acquisition system. It is so expensive to build such system by putting discrete devices together and it would rather be a bulky product. Also most of the existing system receives analog signals. However, if a distance between a receiver and a transceiver is far apart, it can cause a crude signal distortion. Therefore a signal correction circuit is essential for distortion reduction in the system. In this work, we developed an ASIC for PET. A module of the ASIC includes adjustable gain transimpedance amplifier, two comparators and digital logics. The signals from detectors are amplified for each channel. The amplified pulse was split into two signals and each signal is fed into two comparators each with different reference levels. Then an XOR gate combined the outputs coming out from each comparator. The energy information of a detected radiation can be derived from the output of the XOR gate by using time of threshold. The timing and position information is measured using a rising edge from the comparator with low level reference. Therefore, the ASIC can extract the information of time, energy, position and thus the designed chip fulfills the necessary conditions for radiation imaging. The characteristics of designed amplifier are shown as follows: it has a gain of 42.7dB, bandwidth of 650.7MHz and phase margin of 60 degree. In case of the comparator with hysteresis, its rising and falling time is 2ns. The output of module is two bits digital signals. The designed ASIC can improve performance of PET in many ways. First of all, the ASIC has only digital outputs and therefore, a correction circuit for analog signal distortion can be ignored. Secondly, it is possible to cut down the system production cost because the volume of the system is reduced due to the size reduction in ASIC

The conventional front-end electronics for PET imaging consist of an energy circuit and a timing circuit. A single channel in front-end electronics typically requires 3 amplifiers, a TDC and an ADC. This is neither cost-efficient nor power-efficient. The situation becomes more complicated when the detectors are constructed with arrays of silicon photomultipliers (SiPMs). In this paper, we present a novel front-end electronic design using sigma-delta (S-?) modulation. The new design needs only one analog amplifier, one differential digital input port and one digital output port from a FPGA. Both the energy and timing calculation are implemented in FPGA firmware. A Simulink model is established to simulate and evaluate the circuit design and the sample data processing. The energy is calculated directly by summing the sequences of 0 and 1 generated by the 1-bit S-? ADC module. The simulation disclosed the non-linear transfer function of the amplitudes of the input pulse and the calculated energy, which can be corrected using LUT(s). The timing is determined either directly by measuring the timing of first pulse generated by the 500MHz S-? ADC (timing resolution: 2ns), or by measuring the leading edge of the first pulse generated by FPGA differential input using a FPGA-based TDC (timing resolution: ~220 ps). We conclude that the front-end electronics based on sigma-delta modulation provides a cost- efficient and power-efficient way to measure the energy and timing of analog pulses. Only 3 digital pins are required from the FPGA to construct an analog channel. The amount of FPGA resource (logic cells) required for every channel is also very small. Thus, a single low-cost FPGA is potentially able to read out hundreds of analog channels.

Tsinghua University cosmic MUon Tomography facilitY (TUMUTY) was built in 2013 based on large-scale MPRC detectors. In this paper, we present a new prototype of the upgraded readout system together with the performance. In the prototype, an improved encoding readout method was utilized. With the help of the method, n channels of readout electronics can process n×(n+1)/2+1 stripes in the case where n is an odd. And the event with a charge distribution between 2 stripes and (n-2) stripes can be decoded without position ambiguities. The implemented readout electronics consists of fast preamplifier and high-speed waveform sampler. The amplified current pulse from the detector is digitized and then processed with Digital Pulse Process (DPP) methods.

Silicon photomultipliers (SiPM) are increasingly being employed in a variety of applications where the ability to operate at extremely low light levels and the time resolving capabilities of the measurement system are of key importance and several alternatives have been proposed in the literature for the front end amplifier (FEA) architecture which best suits the peculiar characteristics of such signal source. The best performance is obtained by optimizing the design parameters of the whole system SiPM+FEA, rather than considering the SiPM and the FEA as standalone devices, possibly including also the interconnection parasitics. Therefore, a design problem arises which addresses the identification of the best combination of SiPM+FEA for the target performance to be attained. Here we consider three basic alternatives for the FEA architecture, suitable to be implemented in integrated circuit CMOS technology: the charge sensitive amplifier, the open loop voltage amplifier and the current buffer and compare them from the point of view of the maximum achievable intrinsic time resolution. In particular, all the considered cases exploit the same amplifier structure, based on a transconductor loaded with a parallel combination of a resistor and a capacitance, which sets the bandwidth of the circuit. Extensive numerical simulations and some laboratory experiments have been carried out to validate the results of the proposed comparison between different FEA structures and will be included in the final version of the manuscript.

Abstract: A 1.2V 12-bit 20MS/s fully differential asynchronous SAR (Successive Approximation Register) ADC is presented. Compared to the conventional capacitor switching procedure, the presented scheme achieves high-speed and low-power operation thanks to the monotonic capacitor switching and asynchronous techniques. The average switching energy and total capacitance are reduced by about 80% and 50%. Moreover, because of the input common mode voltage gradually converges to the lower input voltage in the conversion procedure, the noise due to the common mode variation is reduced. A new high-speed, low-noise, low-offset comparator is implemented to fulfill the noise and offset requirement. The prototype ADC was designed in UMC 110 nm CMOS technology and submitted for fabrication in November 2014. The prototype is received at the beginning of May 2015 due to the fabrication delay. The measurements and characterization is ongoing and the results will be presented during the conference.

Optical and scintillation properties of crystalline CdF2 were investigated. Theoretically, Auger-free luminescence is predicted in CdF2 and our aim is to study emission origins of CdF2. In scintillation spectrum, intense emission appeared at 420 nm with a weak emission around 350 nm. The scintillation decay profiles were decomposed into two exponential decay curves with the lifetime constants of 1.75 and 25.5 ns. Then, temperature dependence of scintillation of CdF2 was compared with conventional BaF2 scintillator. In addition, excitation spectrum of VUV wavelength was studied at synchrotron facility (UVSOR, Aichi, Japan). Taking into account optical and scintillation properties in the present work, a valid scenario of CdF2 emission would be related to a marginal emission at color centers and exciton, and these emission wavelengths would be quite overlapped.

LuLiF4 crystals doped with 0.1, 0.5, and 1 mol% Ce were prepared by Tokuyama Corp. and their optical and scintillation properties were evaluated. In X-ray induced radioluminescence spectra, an emission due to Ce3+ 5d-4f transition appeared around 310 and 330 nm. In scintillation decay time profiles under pulse X-ray excitation, the primary decay times of LuLiF4:Ce were 63, 73, and 91 ns, for the doping concentrations of 0.1, 0.5, and 1.0 %, respectively. When 137Cs 662 keV gamma-ray was irradiated, the scintillation light yields were estimated to be 1500 ± 200, 2900 ± 300, and 3500 ± 400 ph/MeV for the Ce doping concentrations of 0.1, 0.5, and 1.0 %, respectively. In addition, light yield nonproportionality and energy resolution as a function of gamma-ray energy were investigated. In the conference, detailed scintillation characteristics will be discussed in addition to the basic optical properties.

In this work, we investigate basic optical and scintillation properties of 3% Eu doped SrI2 and non-doped SrI2 crystalline scintillators. The aim of this work is to discuss the nature of scintillation in nondoped SrI2 by comparing with the Eu-doped one. In X-ray induced radioluminescence, emission peak appeared at 430 nm in the Eu-doped sample while the non-doped SrI2 exhibited some emission bands around 360, 410, 430, and 540 nm. X-ray radioluminescence spectra were also investigated at different temperatures from 10 to 300 K. In the scintillation decay curve, the 5d-4f emission of Eu2+ is dominant and the decay time constant is 1.3 us, while the time constant is much smaller (450 ns) without Eu-doping. Taking into consideration optical and scintillation properties, origins of each emission in the non-doped sample will be discussed.

Nuclear non-proliferation applications and monitoring of special nuclear materials (SNMs) prefer low-cost detector solutions that provide efficient gamma-ray and neutron detection in combination with neutron/gamma pulse shape discrimination (PSD). Among the inorganic and organic detector choices, recently developed plastic scintillators can be fabricated in large sizes at low cost and show good neutron detection efficiency in combination with excellent neutron/gamma PSD. Unfortunately, these plastic scintillator have low density and effective Z limiting gamma-ray detection to gross counting. In this paper we report on the fabrication and characterization of metal-loaded plastic scintillators. Research at RMD has focused on plastic scintillators that provide gamma-ray spectroscopy as well as fast neutron detection whereby discrimination between gamma-rays and neutrons is accomplished using pulse shape analysis. We will show that our plastic scintillators have a decent light output (up to 9,000 ph/MeV), a fast scintillation decay, and exhibit very good neutron-gamma PSD with a Figure of Merit (FOM) of up to 2.6 at 1 MeVee. Moreover, gamma-ray spectroscopy was performed and an energy resolution of about 16% (FWHM) at 662 keV was obtained.

Strontium iodide (SrI2(Eu)) is a promising spectroscopic detector for use in both nuclear security and medical imaging due to its excellent energy resolution and low internal background radiation. A cubic form is preferable when coupling with a silicon-based photosensor in order to build an array detector for use in applications such as Compton cameras. Here, cubic SrI2 crystals with 10 mm sides were fabricated and evaluated. The cubic SrI2 samples coupled to an avalanche photodiode exhibited an energy resolution of approximately 3.6% at 662 keV when using a shaping time of 3 µs. An increase in both light output and energy resolution was also observed at lower temperatures. The excellent energy resolution of these devices indicates that these crystals are promising potential detectors for use in Compton cameras and other imaging detectors.

We have prepared many kinds of high quality scintillation crystals successfully by the “Liquinert” process. “Liquinert” means non-wetting state of molten materials with container or crucible at high temperature. Many metallic halides scintillators, for example NaI(Tl), LaBr3(Ce ), SrI2(Eu) and CeBr3 have heavy hygroscopic nature and contain some amount of water in their raw materials. So as to obtain high quality crystals of them, it is very important to remove residual water from these raw materials perfectly. The “Liquinert” process is very powerful for removal of a very small amount of residual water from halides raw materials and from process environment. This process is realized by the sequential two steps, (1) dehydration procedures by vacuum pumping under heating and (2) effective removal of a minute amount of residual water by Reactive-gas atmosphere processing. The perfect removal of it during this process prevents from the incorporation of OH- and/or O2- impurities into crystals and from wetting of melt and sticking of crystal with crucible. We applied this to prepare many kinds of metallic halides crystals for long time. The application examples are CsI(Tl), pure CsI, NaI(Tl), SrI2(Eu) for scintillators . Recently, we have successfully prepared SrI2(Eu) single crystals by the “Liquinert” process. We got many size of SrI2(Eu) single crystals with diameter of 7mm, 10mm, 25mm, 38mm and 50mm. These crystals are cut and polished in the shape of 10x10x10mm cube orf25,38 and 50mm cylinder. These are encapsulated in aluminum containers and hermetic sealed. The 10x10x10mm cube scintillator was evaluated by a Si-PM and cylinder one was evaluated by a PM. We got 3.0~3.6% of energy resolution at 662KeV with 1.5 mol % Eu concentration of SrI2(Eu) cube and cylinder detectors. From these results, we have confirmed the effectiveness of the “Liquinert” process by preparing many kinds sized high quality SrI2(Eu) scintillation crystals.

Recently, the improvement of scintillation properties in Ce:(Lu, Y) ₂SiO₅ (Ce:LYSO) by divalent cations co-doping (e.g. Mg²⁺, Ca²⁺) was reported. In our previous contribution, we reported on the 0~1000 ppm Mg co-doping effect in the Ce:(La, Gd)₂Si₂O₇ (Ce:La-GPS) single crystals grown by the Czochralski process. It was presented that even 100 ppm of Mg caused shortening of the decay time (~10%) as well as a degradation of the light yield (< 20%) depended on the Mg concentration. In this study, influence of the divalent co-doping effect of Mg²⁺, Ca²⁺, and Sr²⁺ on the scintillation and the optical properties in the Ce:La-GPS system is investigated. The 1 inch diameter single crystals were grown by Cz process, and thier solidification fraction were ranging from 30 to 50%. The transmittance of grown crystals had similar absorption derived from 4f–5d transition of the Ce³⁺. In the Sr co-doped sample, its transmittance spectra degraded from about 600 nm to 360 nm, while the other specimens had constant transmission. Scintillation properties were measured with a gamma ray source (¹³⁷Cs, 662 keV) for Mg, Ca, and Sr co-doped Ce:La-GPS single crystals and Ce:Gd2SiO5 (Ce:GSO) used as a standard. Comparing the location of the photopeaks, the co-doped samples showed 3.7~4.4 times higher light output than the Ce:GSO. The scintillation decay times of Mg, Ca, and Sr co-doped samples were ~56 ns, ~56 ns, and ~57 ns, respectively.The details of the above mentioned results and other scintillation and optical properties such as temperature dependence of luminescence intensity will be presented and discussed.

The position sensitivity of a thick, cylindrical and continuous 3” x 3” (7.62 cm x 7.62 cm) LaBr3:Ce crystal with diffusive surfaces was investigated. Nuclear physics basic research uses thick LaBr3:Ce crystals (> 3cm) to measure medium or high energy gamma rays (0.5 MeV < E?< 20 MeV). The crystal was coupled to four Position Sensitive Photomultipliers (PSPMT). In order to simplify the system, the acquired signals were grouped into 4 or 16 segments. An event by event analysis performed using a collimated 137Cs source shows position sensitivity resolution of the order of about 2.3 cm. A case of Doppler broadening induced by a moving source was simulated using a 88Y source and lead shielding leaving a window 1 cm wide and 7 cm high.

Nuclear non-proliferation efforts rely on the ability to detect and identify fissile materials through their signature decay products, namely neutrons and gammas. Presently available technology for the detection and identification of X-ray and gamma-ray radiation is based upon semiconductor technology and scintillator based detectors, the latter category providing more economical alternatives to the high production costs of HPGe and CZT. The search for new scintillation materials has resulted in the discover of many new ternary compositions which exceed the spectroscopic performance of NaI:Tl (6-7% FWHM at 662 KeV). In this report, we present a new high performance ternary metal halide scintillator, KCaI3 (KCI) with a density of 3.8 g/cm3, belonging to the ABX3 family of compounds which contain many materials with promising extrinsic scintillation properties. Preliminary crystal growth experiments of KCI doped with 3 at% europium Ø17mm using the Bridgman method result in single crystals with light yield in excess of 70,000 ph/MeV. For small crystals a few mm3 in volume, pulse-height spectra under gamma source excitation has achieved a measured energy resolution of ˜3% at 662 KeV. Our current research has focused on scaling up growth of KCI to Ø 1” with the aim of maximizing spectroscopic performance of detectors approaching 1 cubic inch, a requirement for domestic security applications. In our efforts to optimize the composition, we performed growth experiments at Ø22 mm under identical conditions with varying Eu activator concentrations. A comparison of the spectroscopic performance for KCI crystals over 1cm3 in volume with different concentrations of Eu2+ is presented.

Several members of the elpasolite scintillator family have recently been under investigation as promising gamma and/or thermal neutron detectors. These crystals tend to display good gamma energy resolution and linearity of response, as well as sensitivity to thermal neutrons through capture on Li-6. We have performed an investigation into the scintillation processes and performance of both Cs2LiLaBr6-xClx:Ce (CLLBC) and Cs2LiYBr6:Ce (CLYB) by performing a thermal cycle over the range of -20 to +50° C. At increments of 10°, we acquired data with both a waveform digitizer and charge-integrating electronics. We then identified the distinct decay components of the average neutron and gamma waveforms, and evaluated the energy resolution, thermal neutron gamma-equivalent energy, and pulse shape discrimination performance.

Two stilbene crystals were coupled to low-noise silicon photomultipliers (SiPMs) to assess the assemblies’ time resolution for use as elements in a handheld dual-particle scatter camera. Pulses were digitized from a measurement of Na-22 and digital constant fraction discrimination (CFD) was performed to determine the time of each pulse. The crystals were then coupled to photomultiplier tubes (PMTs) and the measurement was repeated. The full width at half max (FWHM) of the time-difference distributions was used to determine the time resolution of the detector assemblies. The time resolution when using the SiPMs was better than 1 ns and comparable to that of assemblies using PMTs.

Langasite-type single crystals with A₃BC₃D₂O₁₄ chemical composition (A = La, Ca, Sr, Ba, B = Nb, Ta, C = Al, Ga, D = Si, Ga) have been investigated as a piezoelectric single crystal due to the high piezoelectric properties. We have investigated and reported the luminescence and scintillation properties of the langasite-type single crystals as a scintillator. Ca₃NbGa₃Si₂O₁₄ (CNGS) and Ca₃TaGa₃Si₂O₁₄ (CTGS) single crystals are one of langasite-type material with an ordered structure and the scintillation properties were reported. On the other hand, Sr₃NbGa₃Si₂O₁₄ (SNGS) and Sr₃TaGa₃Si₂O₁₄ (STGS) crystals are also langasite-type material and they have larger density and effective atomic number than the CNGS and CTGS crystals. Therefore, in this study, we grew SNGS and STGS single crystals and their luminescence and scintillation properties were investigated to evaluate the SNGS and STGS crystals as a scintillator and a host material. SNGS and STGS single crystals were grown by the µ-PD method and during crystal growth, width of the liquid-solid interface was ~200 µm. As-grown crystals had ~f3 mm diameter and 3~4 cm length. Both crystals indicated light red color and they were high transparency. The polished specimen indicated absorption peaks around 400 and 500 nm in the transmittance spectrum. The color of crystals are considered to be due to the absorption. In the RL spectrum of SNGS crystal under a-ray irradiation, emission peak around 420 nm was observed and the emission peak also appeared in the RL of CNGS and CTGS crystals. Other luminescence and scintillation properties will be reported.

ecently, our group reported about Ce-doped Gd3(Al,Ga)5O12 (Ce:GAGG) single crystal and scintillation response of about ~90 ns at emission around 520 nm, prospective light yield of about 56000 photon/MeV, and density of 6.63 g/cm3. Improvement of scintillation performance by co-doping with alkali earth AE2+ ions in Ce activated scin-tillators such as, LSO:Ce,Ca, YSO:Ce,Ca , LaBr3 :Ce,Sr and LuAG:Ce,Mg. Recently, Mg and Ca co-doped GAGG was reported and noticeable decay time acceleration was obtained. In this study we investigated the relationship between Mg concentration, and optical, luminescence and scintilla-tion properties of Mg,Ce:GAGG crystal grown by the Czochralski (Cz) method. Furthermore 3inch size single crystals of Mg,Ce:GAGG was successfully grown. The de-tailed results on chemical analysis, light yield, decay time and timing resolution will be reported.

LiF/CaF2/LiBaF3 eutectic scintillators were grown by the m-PD mehod at the composition of eutectic point. In the eutectic each phase were well dispersed to transverse direction and slightly aligned along the growth direction. Expected emission peak was observed at 420 nm ascribed to Eu2+ 4f-5d transition from Eu:CaF2 under X-ray excitation. In this eutectic, Li concentration in the LiF/CaF2/LiBaF3 eutectic is around 67.9 mol%. This is the advantage for neutron detection because 6Li has high reactive cross-section to neutron. The grown eutectic scintillator is promising for high sensitive neutron imaging application such as detector of neutron diffraction, nondestructive inspection, etc. In our presentation, relation between chemical composition of starting materials, growth rate, volume ratio of eutectic will be discussed. Furthermore other scintillation properties will be reported.

Ce1%:Gd3(Scx,Al1-x)5O12 (x= 0.3, 0.4) crystals were grown by the Czochralski (Cz) method. The x= 0.3 sample showed single garnet phase and the x= 0.4 sample showed perovskite phase as a secondary phase. Gd and Sc admixture shifted the 4f-5d Ce3+ excitation and emission bands to longer wavelengths comparing with a Ce:Y3Al5O12 single crystal sample. The light yields of x= 0.3, 0.4 and Ce:YAG samples were around 5,000, 6,000 and 12,000 photon/MeV, respectively.

Eu doped SrI₂ single crystal have been energetically investigated as a next-generation gamma-ray scintillator with high light yield and energy resolution. Eu:SrI₂ scintillator crystals with strong hygroscopic nature have been grown by a Vertical Bridgman (VB) method using a quartz ampoule. On the other hand, we developed a modified micro-pulling-down (µ-PD) method with a removable chamber and reported the results on crystal growth and scintillation properties of halide scintillator crystals as represented by CeBr₃, Ce:LaBr₃ and Eu:SrI₂ using the modified µ-PD method. However, Eu:SrI₂ crystal has relatively slow decay time (~ 1 µs) for some applications due to the usage of emission by the forbidden transition of Eu²⁺ ion. On the other hand, Pr doped scintillator crystals as represented by Pr:Lu₃Al₅O₁₂ and Pr:Y₃Al₅O₁₂ have faster decay time compared to Eu doped scintillators. Therefore, in this study, we grew Pr doped SrI₂ single crystals and their scintillation properties were investigated. Pr:SrI₂ single crystals were grown by the modified µ-PD method using the removable chamber. During crystal growth, the liquid-solid interface was stable below the crucible and the diameter was limited by the hole of crucible. As-grown Pr:SrI₂ single crystal with approximately f2 mm diameter had light green-color and polished crystal indicated high transparency. Radioluminesence (RL) spectrum of polished Pr1%:SrI₂ single crystal under X-ray irradiation was measured using the sealed sample container. In the RL spectrum, emission peak around 500 nm was observed and the emission peak was attributable to the Pr³⁺ ion. Details of crystal growth and other scintillation properties will be reported.

ZnO is a promising nanomaterial for use as a scintillator because of its attractive properties such as sub-nanosecond decay time, medium density (5.6 g/cm3) and high light output efficiency. It has a direct bandgap of 3.37 eV at room temperature and its large exciton binding energy (60 meV) makes it a very efficient emitter. Due to its unique properties, it has attracted attention for use as a radiation detector. ZnO nanorods were grown and tested for use in a-particle detector and in thermal neutron detector systems when combined with a radiator such as Li-6. . The ZnO nanorod scintillators were grown via a low temperature hydrothermal method. The main advantages of the low temperature hydrothermal synthesis are: a low growth temperature (<350 °C), use of simple equipment, low cost, less hazardous and the possibility of scaling up to large growth area. Other growth methods such as MOCVD can be used to grow high quality single crystalline films, but these methods are also costly and slow processes. The photoluminescence and and a-particle detection properties of the ZnO nanorods grown were investigated. Their potential for use in thermal neutron detection using a radiator was also investigated. Based on the observed performance, the low temperature hydrothermal growth method shows promise for low-cost growth of ZnO scintillators for use as a-particle detector and in thermal neutron detector systems.

In the present work, we have made Monte Carlo simulations of the response of 1"x 1" LaCl₃(Ce) and 1" x 1" LaBr₃(Ce) scintillation detectors using the radioactive sources emitting two gamma rays in cascade, namely, ⁶⁰Co, ⁹⁴Nb, ⁴⁶Sc and ²⁴Na for different values of source-detector separation. These simulations were done using GEANT4 toolkit that include radioactive decay module and general particle source (GPS) module. Energy spectra were generated for each of these double gamma emitters and absolute activities were calculated using conventional sum-peak method proposed by Brinkman et al., [Int. J. Appl. Rad. Isot.14 (1963)153] and modified sum-peak method proposed very recently by Ogata et al., [Nucl. Instr. Meth. A 775(2015)34]. In order to validate the simulated results, we have carried out experimental investigations using a calibrated ⁶⁰Co source. The measured activities are found to be in very good agreement with the simulated activities

Recently, the pyrosilicate crystals described with a A₂Si₂O₇ formula, have been studied as scintillation materials, where the A is rare-earth atoms. The Gd₂Si₂O₇ (GPS) and Lu₂Si₂O₇(LPS) are the recently most investigated systems. These materials have good light output or/and good energy resolution. However, they do not melt congruently (e.g. Gd₂O₃ – SiO₂ system), and therefore the growth from the melt is difficult. In order to obtain the congruent composition, the material was doped with approximately 10-50% La. Then the Ce:(La, Gd) ₂Si₂O₇ (Ce:La-GPS) scintillator crystals with a good energy resolution (FWHM) of 5% at 662 keV were obtained. Recently, we have succeeded in growing the larger size Ce:La-GPS bulk crystals by the Czochralski (Cz) process with a diameter of up to 2-inch. At a room temperature, the light output was approximately 40,000 photons/MeV for both samples from 1 and 2 inch bulks. The 2-inch sample had energy resolution (FWHM) of 5-6 % which is similar to that of the sample grown by the FZ method and 1-inch Ce:La-GPS grown by Cz. Even at 150°C, the Ce:La-GPS had a good energy resolution (FWHM) of approximately 8% at 662 keV. On the other hand, Ce:Gd₂SiO₅ which is conventional scintillator for oil well logging, showed the energy resolution of roughly 15% using the ruggedized PMT. Moreover, we assembled Ce:La-GPS array for gamma camera in medical imaging, and succeeded in obtaining 2-dimensinal image in flood-field irradiation using a ¹³⁷Cs source with a Multi-Pixel Photon Counter array. We show the scintillation properties and their applications in this paper.

A common configuration for the scintillator crystals used in gamma radiation detectors for PET scanners is pixelation. The size of these pixels, the crystal surface treatment and the reflector thickness inserted between crystals directly affects the energy and the spatial resolution as well as the sensitivity of the detector. The fabrication of pixels is laborious, complex and expensive. The goal of our effort is to develop a PET detector prototype for the evaluation of the fabrication of pixels within monolithic scintillators, using the proven technique of sub-surface laser engraving with a Nd:YAG laser, guided by the results of light propagation simulations. We evaluated our simulations and surface treatment techniques on a number of different scintillating crystals such as BGO, GSO and LYSO. Measurement and analysis methods to demonstrate the reflective quality of the engraved surfaces have been developed based on microscopy imaging and image processing techniques. A readout setting based on a PS photomultiplier provided field flood diagrams for the different engraving configurations and crystals. Configurable engraved surface transparency or pixel geometries as well as depth-of-interaction encoding techniques can be tested. Our results demonstrate that pixels, engraved with this method can also be configured to compensate for the multiplexed readout penalties and preserve the detector performance. Such modifications of the engraving pattern take place at practically no cost and constitute a highly promising solution for industrial fabrication, reducing substantially the cost of the detector.

Rad-hard glass compositions are described using Ba-, Bi-, and Ge-fluorophosphates, combining properties of alkali-free fluoride and phosphate glasses with heavy metals (transition metals, rare earths up to 20 wt%), over a wide glass-former domain. Densities range from 4.2-4.5 g/cc. The dielectric breakdown field is higher than any other known glass. Radiation damage testing shows no loss of transparency for gamma doses larger than 1 GRad, and neutron doses exceeding 10^20 n/cm^2. These glasses are more radiation resistant than purified high OH- quartz. Doping with Y, Ce and Yb produced bright scintillation, with 0.5% Ce having a primary decay constant less than 12 ns. The mechanism for radiation resistance is described, and source, beam and raddam tests, and light yields and optical properties are presented. This material is applicable to total absorption calorimeters (Cerenkov or scintillation), and tile sampling scintillating calorimeters, including Shashlik-like calorimeters and Cerenkov-compensated calorimeters, as well as power delivery fibers, laser glass amplifiers and fibers, and rad-hard optics. The cost of the glass per optically finished cc or kg is likely to be much less than crystalline scintillators such as LYSO.

Radiation therapy has been widely used to treat the tumor. However, it is said that some medical accident occur due to over dose [1]. Thus, real-time dose-monitoring system is expected to save the accident. Human body has an optical transparent area around near infra-red region (650 to 1200 nm) [2]. Using this “window”, a novel real-time dosimeter system can be developed with infra-red emission scintillators; When X rays or other radiation particles for medical use generate the scintillation light in the infra-red scintillator, the luminosity or count rate of infra-red scintillation light can be read out of the patient. Since the dose is related to the luminosity or count rate, we can measure the dose with a real time (Fig. 1). Ytterbium-doped crystals are widely used as near-infra-red laser materials, and Yb:Y3Al5O12 (Yb:YAG) has an emission wavelength of around 1030 nm[3,4]. Thus, we investigated scintillation properties of Yb-doped laser materials in the infra-red region in order to find novel infra-red scintillators. Recently, Gd3Al2Ga3O12 (GAGG) crystal was studied as a visible-emitting scintillator. The Ce-doped GAGG crystal has various advantages such as [5]: (i) large density (6.68 g/cm3) and high stopping power, (ii) non-hygroscopic nature, (iii) non-intrinsic background due to radio-active isotopes and (iv) higher light output of more than 40,000 photon/MeV (662 keV gamma rays). Thus, this scintillator crystal has found its application in gamma-ray detection.

Ce:LaBr3 scintillator crystal has been widely used for some applications for detection of ?-ray, however the existence of 138La in the crystal limits the choice of applications. Therefore, CeBr3 scintillator crystal is expected to be next-generation ?-ray scintillator due to the high light yield, high energy resolution and fast decay time [1]. Many halide crystals including CeBr3 have high hygroscopicity and it is difficult to grow their single crystals with high quality and intrinsic scintillation properties. However, recent development of growth technique for halide single crystal enabled to obtain their single crystals with high quality and their halide scintillators are raising even more expectation for applications as a single crystal. In the previous report [2], Ce doped PrBr3 [Ce:PrBr3] crystals with Ce 5 and 20% concentrations indicated faster decay time than Ce5%:LaBr3 crystal (16 ns). However, the light yields of Ce:PrBr3 crystals were greatly decreased by the Ce doping. In this study, we focused on Pr doped CeBr3 scintillator crystals with small Pr concentration. If the decay time can be improved by the doping of small Pr concentratoin, Pr:CeBr3 crystal can indicate faster decay time than CeBr3 crystal without large decrease of light yield.

A scintillation detector consists of a scintillator coupled to a photodetector, which in most cases is a photomultiplier tube (PMT). Recent advancements in Si-based photomultipliers (SiPM) created an alternative solution, which could lead to smaller and less fragile detectors. Still, the main drawback of these devices is their active area. While the active area of PMTs can easily be counted in square inches, typical active area of a SiPM device is 6x6 mm2. This represents a challenge, since it reduces the efficiency of light collection when larger volume (area) scintillators are used. The reduction in light collection efficiency directly impacts the energy resolution. Still, the large scintillator sizes are required to achieve good detection efficiency. Recently, we initiated studies of the performance for detectors constructed using selected SiPMs coupled to larger volume scintillators. In particular, we looked at 1-inch right cylinders since this seems to be the lowest practical volume for many applications. We are evaluating SiPMs from Hamamatsu, SensL and KETEK coupled to a number of various scintillators (e.g. CeBr3, CLLBC, CsI:Tl) finding the overall performance very good. In this presentation we will report on the results covering the effects of light collection, energy resolution, low energy thresholds, and linearity of response.

Flexible quartz capillary fibers (OD=1mm, ID/OD~0.8-0.9), cladded with low index doped quartz and/or Teflon-AF, have been filled with anthracene scintillator and 3HF wavelength shifter (WLS) by a melt and vacuum inbibition process. Other polcyclic hydrocarbons such as pTP, stilbene or Naphthalene are also well-suited to scintillating/shifting cores, as are some low-melting inorganics such as CeBr3. These pure materials have radiation hardness measured to be between 5-100 MRad, with the quartz capillary exceeding 100 MRad. The resulting scintillating or WLS core, quartz cladding fibers (250-750 µm cores) had a high specific light output when tested with muons. Since about half the radiation damage in plastic scintillator/WLS readout calorimeters is damage in the WLS fibers, readout fibers with rad-hard properties are necessary. Improvements in the techniques, rad-tests, yields and future directions with thin optically emitting films are described.

Photomultiplier tubes (PMTs) have been the primary device for converting optical photons to electronic pulses in scintillation detectors. They are bulky, delicate, and require high voltage and magnetic shielding to operate. The advent of silicon photomultipliers (SiPMs) has made compact scintillation detectors possible due to their mm size in depth, less than 100 V bias, and insensitivity to magnetic fields. Medical imaging detectors and hand-held radiation detectors are some of the applications that have benefited from these SiPMs. Because the cylindrical scintillators are developed for the PMTs and the active area of the SiPMs is small, developments in optimizing the geometry of the scintillators and designing SiPM arrays are required. This paper presents the results of Geant4 simulations for the response of various shapes of scintillators coupled to a 2x2 array of SiPMs. In addition, results of measurements using a PMT with a square mask to simulate the SiPM array will be reported. Using a cubic NaI scintillator with the masked PMT the resolution is 8% for the 662 keV ?-ray which is suitable for spectroscopy. A prototype detector using a 2x2 array of SiPMs is under construction for further testing.

With increasing beam energies and intensities of colliders, the development of radiation-hard scintillators and wavelength shifting fibers has become a crucial path in the future detector designs. The areas of implementation of such scintillators and fibers range from calorimetry to beamline instrumentation to specialized forward detectors e.g. luminosity monitors. The research on the radiation-hard scintillators falls into two categories: Quartz plates (which form a radiation-hard substrate) coated with thin, radiation-hard organic or inorganic compounds, and intrinsically radiation-hard scintillators like Polyethylene Naphthalate (PEN). Here we report on the recent developments supported with results from laboratory and beam test measurements.

Our current research is focused on understanding effects of europium concentration in large diameter crystals of potassium strontium iodide. In this work, we grew 1 inch diameter, single crystals of KSr₂I₅:Eu²⁺, with Eu²⁺ concentrations ranging 0.25 to 4%. In order to evaluate the material’s quality and uniformity when grown in large volumes, specimens measuring at least 1 cm³ were tested.

Submillimeter spatial resolution in Positron Emission Tomography (PET) imaging is physically within reach using highly pixelated detectors with individual readouts. Parallel processing of the signals from densely packed detector arrays requires advanced integration of the front-end electronics. The LabPET II detector front-end module, based on avalanche photodiode (APD) and Time-over-Threshold signal processing, was designed to achieve ~0.8 mm spatial resolution in small animal imaging and to become a generic platform for ultra-high resolution PET imaging scanners.

The basic building block uses a 4×8 crystal array of Lu_1.9Y_0.1SiO₅:Ce (LYSO) scintillator pixels (1.12×1.12×12-mm³) with one-to-one coupling to a 4×8 pixelated APD array mounted on a ceramic carrier. Four of these modules are mounted on a PCB with two 64-channel ASIC interfacing to two detector modules each. Signals from each APD pixel can be individually processed by dedicated dual-threshold ToT channels providing timing and energy data. A calibration of energy with ⁶⁷Ga (300 keV), ⁶⁸Ge (511 keV), ²²Na (511 keV, 1275 keV) and ¹³⁷Cs (662 keV) gamma-ray sources was performed to correct the non-linearity of the ToT signal and obtain energy spectra. Energy and timing performance of the complete front-end module have been evaluated. Results confirm the functionality of the dual threshold ToT circuit implemented in the 64-channel ASIC, as well as the physical performance of the most recent LabPET II version of APD-based detectors for applications in high-resolution PET imaging.

Barium halides (BaX2, X= F, Cl, Br, I) form solid solutions that have been studied in the last years due to their propensity to be excellent scintillators when activated by Eu2+[1-3]. For future commercialization they are also attractive as it is anticipated that the cost and availability of the raw materials will allow for production of affordable crystals, a requirement for large-scale deployment. The main impediment to their large-scale production is the low crystal growth yield and reproducibility of the growth technique. Up to now, they have been synthetized in polycrystalline forms and as small size single crystals by the vertical Bridgman-Stockbarger technique. Here, we report on the development of the Czochralski growth of 1” in diameter crystals of the ternary: BaBrI activated with Eu2+. We grew the stoichiometric compound with 8% Eu according to the optimal value from our previous studies. The liquidus solidus separation of the BaBrI solid solution is very small allowing growth of crystal with uniform composition as demonstrated by the measured scintillation performance. We have recorded energy resolutions of 3.7% homogeneously distributed along the Czochralski grown single crystals and an average of 62,000ph/MeV light output. These values are still below what is expected from that material [2] but we find that the Czochralski process, a commercially viable production tool with high yield, can be used and further developed for growth of the mixed halides. We will present various aspects of the growth process: the subtle seeding scheme, stoichiometry control, melt cleaning procedure and growth parameters.

Cs₂LiYCl₆:Ce (CLYC) is a promising new inorganic scintillator for gamma and neutron detection. As a gamma-ray detector, it exhibits bright light output and better resolution and proportionality of response than traditional gamma-ray scintillators such as NaI. It is also highly sensitive to thermal neutrons through capture on ⁶Li, and recent experiments have demonstrated sensitivity to fast neutrons through interactions with ³⁵Cl. The response of CLYC to other forms of radiation has not been reported. We have performed the first measurements of the response of CLYC to several-hundred MeV protons. We have collected digitized waveforms from proton events, and compare to those produced by gammas and thermal neutrons. Finally we discuss the potential for pulse shape discrimination between them.

Lutetium Oxyorthosilicate (LSO) is an attractive scintillator for positron emission tomography (PET) imaging, due to its relatively high light output, short decay time, and high stopping power. Lutetium has a 2.6% natural abundance of Lu-176, a long-lived (3.78e10 years) radioisotope which generates an intrinsic background within LSO. This low background rate has been capitalized on to perform PET quality checks and measure transmission data. In this work, LSO was exposed to the neutrons produced by the O-18(p,n)F-18 reaction in a Siemens Eclipse Cyclotron, to selectively alter the intrinsic background rate. The cyclotron was run for a total of 1827 microamp-hours over two weeks, with proton energy of 11 MeV. Ten LSO pixels (4x4x20mm) were placed in locations selected for a desired neutron energy range. The range of neutron energies produced permitted the Lu-175(n,?)Lu-176 and Lu-176(n,?)Lu-177 reactions. Three of the pixels were encased within borated polyethylene to further moderate the neutrons. The pixels were characterized as scintillators to determine if they had been damaged by irradiation. Gamma ray spectroscopy was performed for several weeks to evaluate the activation engendered. Scintillation properties were not changed, and the expected activation occurred.

In the last few years a considerable interest to the Eu-activated mixed alkaline-earth halides (solid solutions of two binary halides such as BaCl2, BaBr2 and BaI2) has emerged due to their unique scintillator properties for the radiation detectors application. The best examples of leading compounds in the Ba-based family are BaBrCl and BaBrI with a light output of 52,000 ph/MeV and 97,000 ph/MeV, and an energy resolution of 3.55% and 3.4% at 662 keV, respectively [1, 2]. Here we explore co-doping strategies for two purposes with the ultimate goal of combining the two: (1) improve the resistance of the crystals to fracture during the growth and (2) improve the energy resolution and/or light output. We conducted a study on the impact of Na, K, Rb and Cs co-dopants primarily used for toughening BaBrCl:Eu crystals and we present the impact of these co-dopants on the scintillation properties. Mechanical/elastic properties and cracks propagation data obtained from micro-indentation measurements, and the concentration dependencies will be presented. We will also present the gamma ray characterization of the crystals as well as optical and x-ray the temperature dependent scintillation properties. Special attention will be given to co-doped samples that show a major improvement in their scintillation performance compared to the undoped sample in an attempt to find a good balance between performance and ease of growth. References [1] G. Bizarri, E. D. Bourret-Courchesne, Z. W. Yan, and S. E. Derenzo, IEEE Transactions on Nuclear Science, 58 (2011) 3403. [2] E. D. Bourret-Courchesne, G. A. Bizarri, R. Borade, G. Gundiah, E. C. Samulon, Z. Yan, and S. E. Derenzo, Journal of Crystal Growth, 352 (2012) 78.

Fast scintillators such as LaBr₃(Ce) and CeBr₃ offer new opportunities in gamma-ray detection with good energy and time resolution. Recently digital signal processing has become a standard in data acquisition for multi-parameter set-ups, since they have a very good performance in terms of energy resolution, dead time and flexibility. Nevertheless digital methods able to maintain the excellent intrinsic time resolution are still not available. In this paper we report on the results of digital processing of signals of LaBr₃(Ce), CeBr₃ and BaF₂ detectors aimed at obtaining the best time resolution. As a proof of principle we have used a 4-channel oscilloscope with 1 GHz bandwidth and 4 GSa/s sampling rate. Pulses were acquired, stored in memory and analyzed off-line. For each of the three detectors coincidence measurements were performed at ⁶⁰Co and ²²Na energies against a fast reference BaF₂ + XP2020 detector. Several digital signal processing methods have been used to measure the time resolution for the individual detectors, given as the FWHM of the time distribution with the de-convolution of the reference. Constant fraction, threshold and comparator processing methods were used. The digital processing method that provides the best results is the digital CFD algorithm, yielding time resolution values comparable to those obtained by analog systems. Therefore digital processing is a competitive technique for fast-timing with fast scintillators and it holds a strong potential for its implementation in standard set-ups.

LaBr₃(Ce) crystals unite high gamma detection efficiency, good energy resolution and fast response, and have become the standard in many gamma-ray measurements. Nowadays they are the key element in the application of Ultra Fast Timing method allowing the experimental determination of nuclear lifetimes of excited nuclear states in the range of few nanoseconds to tens of picoseconds. The size and shape of the crystals have a strong impact on the time resolution. We have designed special geometries aimed at enhancing the light collection and thus the time response, and also enhancing the packing factor for the construction ring arrays around a fixed target. In particular two types were designed: a truncated cone shape with 1 in. height and bases of 1.5 in. and 1 in., and a tapered "hybrid" crystal, with a cylindrical section 1.5 in. in the base and 0.65 in. in height and a 1.2 in. long conical section. In this work we have assessed the performance of these special LaBr₃(Ce) crystals and compared them to a standard 1-inch cylindrical one. Analogue signal processing via CFD and TAC is used for the timing. The external CFD delay, the CFD zero-crossing value (Z), and the high voltage have been optimized, leading to excellent time resolutions at ⁶⁰Co and ²²Na comparable to those of the smaller 1-inch cylindrical LaBr₃(Ce) crystal. Monte Carlo simulations of optical photons have been performed using the Geant4 toolkit in order to test the effect of the geometry and the doping in the LaBr₃(Ce) crystals, and to compare to the experimental results, with a reasonable agreement. These simulations are in reasonable agreement with the experiment. They allow a deeper understanding of the key parameters affecting the time and energy resolution of the detectors.

Cerium activated Gd3(Al1-xGax)5O12 (GGAG:Ce) crystals show excellent scintillation performance especially in low energy regain. GGAG:Ce single crystal was grown by Czochralski Method (CZ). Optical transmittance, scintillation properties such as radio-luminescence (RL), light output, decay kinetics and time resolved luminescence were performed between 80K and 500K. It was found that the scintillation efficiency increases with increasing temperature between 80K and 260K followed by a dramatic decrease at temperature above 290K. Temperature dependent of decay kinetics and the time resolved scintillation luminescence will also be presented.

Eu doped SrI₂ (Eu:SrI₂ ) single crystals have been deeply investigated for possible application in radiation detection for its favorable properties such as high light output (over 70,000 photons/MeV) and energy resolution (approximately 3% at 662 keV, FWHM). Most Eu:SrI₂ scintillator crystals have been grown by the Vertical Bridgman (VB) method using a quartz ampoule. On the other hand, we have developed a modified micro-pulling-down (µ-PD) method for growth of halide crystals, since this method have realized faster crystal growth than the VB method. Up to now, Crystals of several halide compounds could be successfully grown despite their high hygroscopic nature. Although, the modified µ-PD method cannot grow a bulk single crystal with a diameter of more than 10 mm, we developed a novel VB method using the µ-PD furnace with the removable chamber to grow bulk single crystals of hygroscopic halide materials. There are some advantages of the novel VB method using µ-PD furnace compared to the conventional VB method. In this study, we developed Eu:SrI₂ bulk single crystals with diameters of up to 2 inch by the VB method using the µ-PD furnace, and the light outputs these crystals were over 70,000 photons/MeV. We show crystal growth and its scintillation properties in this presentation.

Sandia National Laboratories (SNL) is investigating tin loaded polystyrene scintillators for potential gamma-ray spectroscopy application. Research and development of these plastic scintillators require accurate characterization of light yield resulting from a gamma-ray interaction with the organotin compound samples produced. The Compton edge in the measured pulse height spectrum (PHS) is believed as a viable approach for accurate light yield evaluation. To determine the ideal Compton edge in the measured PHS, Fast Fourier Transform (FFT) based gamma-ray spectrum deconvolution was investigated. The FFT technique is one of the many well-established techniques in spectral deconvolution. Results from FFT implementation was encouraging and showed significantly enhanced and sharper Compton edge. Several efforts are being carried out to validate results and further suppress noise related features in the deconvolved spectrum.

Radiation therapy has been widely used to treat the tumor. However, it is said that some medical accident occur due to over dose or other factors. Thus, real-time dose-monitoring system is required to save the accident. Here, human body has an optical transparent area around near infra-red region (650 to 1200 nm). Using this “window”, a novel real-time dosimeter system can be developed with infra-red emission scintillators; When X rays or other radiation particles for medical use generate the scintillation light in the infra-red scintillator, the luminosity or count rate of infra-red scintillation light can be read out of the patient. Since the dose is related to the luminosity or count rate, we can measure the dose with a real time. Cr doped Gd₃Ga₅O₁₂ is one of the most known laser crystals in the near infrared region and has been developed, and this is also one of the candidate for the near infrared scintillator. Thus, in this work, we grew Cr-doped garnet single crystals: Cr-doped (Gd_x, Y_1-x)₃Ga₅O₁₂ (x = 0.00, 0.25, 0.50, 0.75, 1.00) crystals and Cr-doped ß-Ga₂O₃. These crystals had red or infra-red emissions originated from d-d transition of Cr³⁺ in the X-ray excited radio-luminescence spectra. In this study, we show the crystal growth and their scintillation properties, and test the X-ray imaging for these novel scintillator irradiated with alpha rays or X rays.

Ce-doped Gd₃(Al, Ga)₅O₁₂ (Ce:GAGG) was found to have high light-yield (~ 46,000 photon/MeV) and good energy resolution (~ 4.9 % at 662 keV, FWHM). Recently, some groups have studied the scintillation properties for some crystals co-doped with divalent or etravalent cation; Ce:Gd₂SiO₅ (Ce:GSO) doped with around 200 ppm Zr⁴⁺ has shown maximum light output which is about 20% larger than that of conventional GSO:Ce. On the other hand, light output of Ce:(Lu, Y)₂ SiO₅ (Ce:LYSO) co-doped with divalent cation (e.g. Mg²⁺, Ca²⁺) was improved compared with the conventional Ce:LYSO scintillator.Here, Ce:GAGG doped with divalent cation, while effect of codoping with tetravalent cation has not been sufficiently investigated for Ce: GAGG. In this paper, we investigate the light output and other scintillation properties of M⁴⁺/Ce³⁺ co-doped GAGG, where M = Zr, Hf. Thus, 1000 and 200 ppm co-doped Ce:GAGG crystals were grown by the micro-pulling down (µ-PD) method, and optical and scintillation properties were investigated. The samples co-doped with Hf4+ had lower light output than the conventional Ce:GAGG by 10-20%. Moreover, The co-doped samples had slower decay time components than the conventional one. We show the detail of the crystal growth and their results in this report.

We have reported the scintillation properties of a (Ce_0.01,Gd_0.90,La_0.09)₂Si₂O₇ (Ce:La-GPS: Cerium-doped lanthanum-gadolinium pyrosilicate)grown by floating zone (FZ) method, as a novel scintillator, and it has a high light output of roughly 35,000 – 42,000 photons/MeV and energy resolution (FWHM) of ~5% at 662 keV. Although the pyrosilicate-group crystals with other rare-earth dopants employing 4f-4f luminescence are not expected to have fast decay time, these materials can be used as X-ray detection scintillators. Especially, scintillation emission wavelength of Eu, Tb, Nd or Pr doped crystals well matches the sensitivity region of a charge coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) camera with high quantum efficiency, which is roughly within 500-700 nm. Thus, RE:La-GPS (RE = Eu, Tb, Nd and Pr) crystals were grown by the floating zone method (FZ) under argon atmosphere, and we found the scintillation emission from Eu, Tb, Nd or Pr doped crystals excited by X rays. Moreover, we succeeded in imaging of X-ray using these material with a COMS camera. In this paper, we show the detail of the crystal growths, measurement setups and their results.

The thin scintillation crystals are required to various fields such as medical imaging, astronomy, because thinner scintillators enable gamma-ray detectors to be better position or angular resolutions. Since thin crystals have low gamma-ray detection efficiency, development of scintillator with a high gamma-ray stopping power is important. Here, Lu has a high atomic number (Zeff) of 71, good attenuation length of 1.16 cm at 511 keV, while this crystal has intrinsic backgrounds from ¹⁷⁶Lu. Hafnium has a high atomic number of 72, and its abundance of radio isotope is less than 0.2%. Thus, Hf-containing scintillators have been searched. SrHfO₃ doped with Ce (Ce:SHO), for example, has attracted as a scintillating material due to a high density of 7.65 g/cm³, a high effective atomic number of 64. However, SHO and other Hf-containing materials have high melting temperatures of over 2500°C. Thus, it is hard to grow the single crystals, while ceramics preparation can be, and ceramics materials have been studied in our group.In this paper, we investigated the optical properties of Ce-doped MHfO3 (M=Ca, Ba, Sr, Gd, Lu) ceramics prepared by spark plasma sintering (SPS) method, Ce/Al:SHO ceramics had light output of ~4,000 photons/MeV. Moreover, we report the other properties such as temperature dependence of the light outputs, quantum yields from room temperature to 180 °C.

In scintillation detectors, radiation tolerance is one of the important properties and many materials were subject to an examination of this property towards the practical applications. In radiation tolerance experiments, one interesting phenomenon, positive hysteresis was discovered. The positive hysteresis is a phenomenon in which the light yield of the scintillator increases after exposure to ionizing radiation. In this study, 60Co gamma-ray was irradiated to famous garnet scintillators, including crystal 1% and 3% Ce doped Gd3(Al, Ga)5O12 (Ce:GAGG), 0.5% Ce doped Y3Al5O12 ceramic (Ce:YAG), 0.5% Ce doped Lu3Al5O12 (Ce:LuAG) ceramic, 0.25% Pr doped LuAG (Pr:LuAG) crystal, and ceramic 1% Ce doped GAGG. As a result, crystal 1% Ce GAGG showed the positive hysteresis. In the conference, radiation tolerance of these scintillators after 800 Gy exposure and the detailed results of the positive hysteresis will be presented

Electronic devices operating in hostile radiation environments, such as those found close to high-energy particle accelerators, can suffer from radiation induced failures. At CERN, the mixed particle and energy radiation fields present at the Large Hadron Collider (LHC) and its Injector Chain can give rise to both stochastic and cumulative effects causing radiation induced failures of exposed electronics and materials, thus directly impacting component and system lifetimes, as well as maintenance requirements. In the framework of the Radiation to Electronics (R2E) project, together with a detailed analysis of available dosimetry and beam monitoring results, several FLUKA Monte Carlo calculations and benchmark studies were carried out in order to evaluate the radiation levels along the LHC Injector Chain. This paper analyses different radiation environments and levels found along the CERN's Injector Chain and presents recent Monte Carlo calculations and benchmark studies in the PSB and SPS accelerators. Author: João Pedro de Carvalho Saraiva (European Organization for Nuclear Research, CERN)

We have assessed the effect of proton radiation damage upon the light yield of liquid scintillator and water-based liquid scintillator in order to determine the effect of accumulated dose upon the performance of 3D proton therapy dose verification systems that use these materials in an active phantom volume. Our results suggest that both liquid scintillator and water-based liquid scintillator exhibit reductions in their light yield after 800 Gy of proton dose of 1.74 ± 0.55 % and 1.31 ± 0.59 %, respectively. Based on these results, we do not expect radiation damage to be a significant problem for such a dose verification measurement system.

Recently, Ce:Gd₃(Al, Ga)₅O₁₂ (Ce:GAGG) and Ce:(La, Gd)₂Si₂O₇ (Ce:La-GPS) have been studied well, and these scintillators were found to have good light outputs and energy resolutions (e.g. better than 5-7% at 662 keV, FWHM). On the other hand, it is not enough to evaluate the radiation hardness for these novel scintillators. Thus, we grew Ce:GAGG and Ce:La-GPS crystals by Czochralski process and study their radiation hardness. Ce:GAGG and Ce:La-GPS samples were irradiated with 80-MeV proton ray particles (total dose: ~200 Gy) at the cyclotron faculty. Here, the above dose (~200 Gy) is approximately equal to shuttle radiation dose (proton) in the International Space Station orbits for one or two years. As the results, the light output and energy resolution were remained constant before and after the 80-MeV proton irradiation. Additionally, emission spectrum was also the same as before the irradiation, and no new emission peak originated by some defects triggered from the high-energy proton was observed. On the other hand, scintillation decay times became slower than the before the irradiation. In this presentation, we show the above results and discuss the radiation hardness.

Radiation hardness is a mandatory requirement for electronic components operating in the high radiation environments of present particle physics experiments. Such is the experiment MEG, in Villigen, Zuerich, Switzerland. It investigates the existence of physics beyond the Standard Model searching a forbidden decay of the positive muon into a positron and a gamma. In MEG the most intense muon beam of the world is used. A background of non-thermal neutrons (Kinetic Energy > 0.5 MeV) is present in the experimental hall produced along such beamline and in the hall itself. In order to check if the Silicon PhotoMultipliers used in the experiment would survive such neutron flux they were irradiated with neutrons of energy greater than 0.5 MeV up to the maximum expected total fluences (10¹³ neutrons/cm²). In this talk we report on the change of their most important electric characteristics measured before and after irradiation : dark current, dark pulses frequency, gain, intrinsic time resolution, capacitance, direct bias resistence, as a function of the integrated neutron flux and temperature.