N4A2  High Energy and Nuclear Physics Instrumentation 3

Thursday, Nov. 5  08:30-10:10  San Diego

Session Chair:  Naomi van der Kolk, Max-Planck-Institute for Physics, Germany; Rainer Novotny, University Giessen, Germany

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(08:30) N4A2-1, Precision Muon Tracking and Trigger at Future Colliders with sMDT Chambers

O. Kortner, H. Kroha, F. Mueller, S. Nowak, R. Richter

Max-Planck-Institut fuer Physik, Munich, Germany
Small-diameter muon drift tube (sMDT) chambers are a cost-effective technology for high-precision muon tracking and trigger at the high background rates expected at future colliders. Chambers of this type are under construction for upgrades of the muon spectrometer of the ATLAS detector at high LHC luminosities. Several chambers have already been installed for LHC run II. The chamber design and construction procedures have been optimized for mass production while providing a precision of better than 10 micrometers in the sense wire positions and the mechanical stability required to cover large areas. The inherent mechanical precision allows for highly accurate monitoring of the absolute alignment of the chambers in the detector. The sMDT chamber design profits from the long experience with the MDT chambers in ATLAS and provides even higher reliability. The chambers are operated with a mixture of argon and CO2 gas at 3 bar and are not susceptive to aging. The rate capability of the sMDT chambers has been extensively tested at the Gamma Irradiation Facility at CERN. It fulfills the requirements for the highest background regions in the ATLAS muon spectrometer at HL-LHC as well as over most of the acceptance of muon detectors at future high-energy hadron colliders. The optimization of the readout electronics to further increase the rate capability of the detectors will also be discussed as well as the use of the sMDT chambers in a highly selective first-level muon trigger as it is, for instance, planned for the upgrade of the ATLAS muon spectrometer at HL-LHC.

(08:50) N4A2-2, LHCb Upgrade: Development of a large Scintillating Fibre Tracker

X. Han

Physikalisches Institut, University of Heidelberg, Heidelberg, Germany

On behalf of the LHCb Scintillating Fibre Tracker Collaboration
The LHCb detector at the Large Hadron Collider (LHC) will undergo a major upgrade during the shutdown 2018/19 in order to collect data at much higher instantaneous LHC luminosity. The expected higher particle multiplicity requires a replacement of the current vertexing and tracking system. It is further planned to read out the data triggerless at 40 MHz. The current main tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre Tracker (SciFi). The SciFi consists of 3 tracking stations with 4 independent planes each (X-U-V-X, stereo angle �5�) and extends over 6 m in width and 4.8 m in height. The total active area is 360 m2. Blue emitting scintillating plastic fibres of 0.25 mm diameter are arranged in a staggered close-packed geometry to 6-layer fibre mats. The mats are 2.4 m long and mirror coated at the non-read end. The scintillation light exiting at the other end is detected by linear arrays of SiPM detectors (128 channels of 0.25 x 1.6 mm2 size). The height of a SiPM channel (1.6 mm) extends over all 6 layers of the fibre mat. The pitch (0.25 mm) allows resolving the clusters of hit fibres of typically 2 or 3 channels width. A custom ASIC, the PACIFIC readout chip, is being developed to digitise the signals from the SiPMs. Additional front-end electronics based on FPGAs will be used to reconstruct hit positions and reduce the data-size. The presentation will introduce the LHCb SciFi detector and discuss the main challenges and strategies: the radiation hardness of the fibres and the SiPMs; the mechanical precision required while building large active detector components; the cooling required to mitigate the effects of radiation damage.

(09:10) N4A2-3, Upgrade of MEG Liquid Xenon Detector with UV-Sensitive MPPCs

K. Ieki

International Center for Elementary Particle Physics (ICEPP), University of Tokyo, Tokyo, Japan

On behalf of the MEG II collaboration
The MEG II experiment is an upgrade of the MEG experiment, which searches for the lepton flavor violating decay, µ+ ? e+?. The goal sensitivity in MEG II is 5×10-14, which is one order of magnitude better than MEG. In order to accomplish this goal, a 900l liquid xenon ?-ray detector will be upgraded in MEG II. The granularity of the xenon scintillation light readout will improve from what we obtained in MEG, by replacing part of the 2-inch photo-multiplier tubes with 12×12 mm2 Multi-Pixel Photon Counters (MPPCs). Thanks to the higher granularity, the energy resolution and the position resolution for the detection of ?-ray are expected to improve by a factor of 2. A UV-sensitive large area MPPC is successfully developed for this upgrade, in collaboration with Hamamatsu Photonics K. K. They have been tested in liquid xenon, showing an excellent performance such as high photon detection efficiency for xenon scintillation light (>15% at expected operation voltage). For the signal transmission, a multi-layer “co-axial” type board has been developed for the PCBs to mount MPPCs. Similar type of board is also developed for the feed-through. We have carried out a mass test of ~600 prototype MPPCs in liquid xenon, using the prototype of PCBs and feed-through. Final model MPPCs (~4000 pcs) are also tested in room temperature, in order to check their performance before installation. According to the results of these measurements, the expected performance of the liquid xenon detector is estimated using Monte-Calro simulation. The results of the tests and the results of the simulation will be presented.

(09:30) N4A2-4, Performances of the NA62 RICH Detector

M. Pepe1, G. Anzivino1,2, M. Barbanera1, A. Bizzeti3,4, F. Bucci3, V. Carassiti5, P. Cenci1, B. Checcucci1, R. Ciaranfi3, V. Duk1, E. Iacopini3,6, E. Imbergamo1,2, M. Lenti3, M. Lupi1,7,8,9, M. Piccini1, C. Santoni1,2, R. Volpe3,6, D. Aisa1,2, M. Bizzarri1,2, C. Campeggi1,2, F. Maletta3, A. Papi1, A. Piluso1,2, G. Scolieri1

1INFN Perugia, Perugia, Italy
2Dipartimento di Fisica e Geologia, Università di Perugia, Perugia, Italy
3INFN Firenze, Sesto Fiorentino (FI), Italy
4Dipartimento di Fisica, Università di Modena e Reggio Emilia, Modena, Italy
5INFN Ferrara, Ferrara, Italy
6Dipartimento di Fisica, Università di Firenze, Sesto Fiorentino (FI), Italy
7Dipartimento di Ingegneria, Università di Perugia, Perugia, Italy
8CERN, Geneva, Switzerland
9Johann Wolfgang Goethe-Universit?t, Frankfurt am Main, Germany
NA62 is the last generation kaon experiment at CERN SPS aiming to study the decay K+?p+ ? ?-bar . The goal of the experiment is to measure the decay branching ratio (O(10-10)) with 10% accuracy, collecting about 100 K+?p+ ? ?-bar events in two years of data taking and assuming a 10% signal acceptance. The NA62 detector must be able to reject background events from decay channels with branching ratios up to 10 orders of magnitude higher than the signal and with similar experimental signature, such as K+?µ+?. To this purpose, good PID (Particle IDentification) and kinematic rejection are required. Precise timing is also needed to correctly associate the p+ with the parent K+ in a high rate environment. The key element of the PID in NA62 is the Ring Imaging CHerenkov detector (RICH). The RICH detector is required to identify p and µ in the momentum range between 15 and 35 GeV/c with a muon rejection factor better than 1%; it is also required to measure the pion arrival time with a precision better than 100 ps and the Cherenkov angle with a resolution better than 80 µrad. The RICH will stand a rate of about 10 MHz being a key element of the NA62 trigger system. At the beginning of the NA62 pilot run, from mid October to mid December 2014, the RICH detector was completely installed and ready to take data. The installation details and the first results on the detector performances and on the PID system of the NA62 experiment will be presented at this conference.

(09:50) N4A2-5, The Building Blocks for the Upgrade of the LHCb RICH Detectors

C. Gotti

INFN and Univ. Milano Bicocca, Milano, Italy

On behalf of the LHCb RICH Collaboration
The RICH detectors of the LHCb experiment at CERN are designed to identify pions, kaons and protons created in high energy proton-proton collisions at the LHC. The choice of the radiators, their geometry and position allow the separation in a wide momentum range, 2 to 100 GeV/c, by detecting Cherenkov photons on 2D planes of ~3 m2 with ~10 mm2 resolution. A substantial upgrade is planned for deployment in 2018, mainly aimed at increasing the event readout speed from the current 1 MHz to 40 MHz, matching the bunch crossing rate of the accelerator to maximize data collection. The current photon detectors will be replaced with multi-anode photomultipliers read out with a new custom front-end chip named CLARO8, whose binary output signals, corresponding to single photon hits, will be further processed by FPGAs and sent off-detector through high speed optical links. The design choices for optical, electronic and mechanical aspects are presented here, together with the measured performance of the prototypes on the test bench and in recent beam tests.