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Gaseous Detectors I

Session chair: Dalla Torre , Silvia (INFN Sezione di Trieste, Trieste, Italy); Azmoun , Bob (Brookhaven National Laboratory, Physics Department, Upton, USA)
Shortcut: N-06
Date: Tuesday, 19 October, 2021, 11:45 AM - 1:45 PM
Room: NSS - 2
Session type: NSS Session


Click on an contribution to preview the abstract content.

11:45 AM N-06-01

Rate capability of large-area triple-GEM detectors and new foil design for the innermost station, ME0, of the CMS endcap muon system (#472)

A. Pellecchia1, 2, M. Bianco3, F. Fallavollita3, D. Fiorina4, L. F. Ramirez Garcia5, N. Rosi4, P. Verwilligen2

1 University of Bari, Dipartimento di Fisica, Bari, Italy
2 INFN, Sezione di Bari, Bari, Italy
3 CERN, Genève, Genève, Switzerland
4 University and INFN Pavia, Pavia, Italy
5 Universidad de Antioquia, Antioquia, Colombia


To extend the acceptance of the CMS muon spectrometer to the region 2.4<|η|<2.8, stacks of triple-GEM chambers, forming the ME0 station, are planned for the CMS Phase 2Upgrade. These large-area micro-pattern gaseous detectors must operate in a challenging environment with expected background particle fluxes up to 150kHz/cm2. Unlike traditional non-resistive gaseous detectors, the rate capability of such triple-GEM detectors is limited not by space charge effects, but by voltage drops on the chamber electrodes due to avalanche-induced currents flowing through the resistive protection circuits (introduced as discharge quenchers). We present a study of the irradiation of large-area triple-GEM detectors with moderate fluxes to obtain a high integrated hit rate. The results show drops as high as 40% of the nominal detector gas gain, which would result in severe loss of tracking efficiency. We discuss possible mitigation strategies leading to a new design for the GEM foils with electrode segmentation in the radial direction, instead of the “traditional” transverse segmentation. The advantages of the new design include uniform hit rate across different sectors, minimization of gain-loss with minimal need for voltage compensation, and independence of detector gain on the background flux shape.

Keywords: gas electron multiplier, rate capability, gaseous detectors, muons, mpgd
12:00 PM N-06-02

Commissioning and installation of the new small-diameter Muon Drift Tube detectors for the phase-I upgrade of the ATLAS muon spectrometer (#600)

E. Voevodina1, G. Eberwein1, O. Kortner1, H. Kroha1, M. Rendel1, P. Rieck1, D. Soyk1, V. Walbrecht1

1 Max-Planck-Gesellschaft, Max Planck Institute for Physics, Munchen, Germany


The Monitored Drift Tubes, as a part of the ATLAS muon spectrometer, are precision drift chambers designed to provide excellent spatial resolution and high tracking efficiency independent of the track angle. Through the life of the LHC and ATLAS experiment, this detector has already demonstrated that they provide precise tracking over large areas. The aim of the ATLAS muon spectrometer upgrade is to increase the muon trigger efficiency, precise muon momentum measurement and to improve the rate capability of the muon system in the high-background regions during the High-Luminosity LHC runs. To meet these requirements, the proposed solution is based on the small (15 mm) diameter Muon Drift Tube chamber (sMDT) technology. The new detector provides about an order of magnitude higher rate capability and allows for the installation of additional new triplet Resistive Plate Chambers (RPCs) trigger detectors in the barrel inner layer of the muon system. A pilot project for the barrel inner layer upgrade is underway during the 2019/21 LHC shutdown. For this reason, the Max Planck Institute for Physics in Munich has built 16 sMDT chambers, each will cover an area of about 2.5 m2. To ensure their proper operation in the experiment, the sMDT detectors have to pass a set of stringent tests both at the production site and after their delivery at CERN. After their installation in the ATLAS muon spectrometer, the muon stations are further tested and commissioned with cosmic rays. The author will describe the detector design, the quality assurance and certification path, as well as will present the experience with the chamber tests, the integration procedure and installation of the muon stations in the ATLAS experiment.

Keywords: ATLAS, muon spectrometer, gaseous detector, small-diameter Muon Drift Tube detector, HL-LHC upgrade
12:15 PM N-06-03

WithdrawnDesign and Simulation of a Parallel Plate Gas Electron Multiplier (#1321)

L. Liu1, 2, Y. Yang1, 2, Z. Zhang1, 2

1 Tsinghua University, Department of Engineering Physics, Beijing, China
2 Key Laboratory of Particle & Radiation Imaging, Ministry of Education, Beijing, China


Micro-Pattern Gaseous Detectors show the high throughput rate and high position resolution. However, the high cost and harsh conditions needed limit their applications. This paper proposes a Parallel Plate Gas Electron Multiplier (PPGEM) based on the general Print Circuit Board (PCB) technology. The prototype detector shows the electrons’ collection efficiency of 10.6%, the ion backflow rate of 5.6%, and the electrons’ gain of 323. If the thickness of cathode PCB of PPGEM can be reduced from 0.4 mm to 0.2 mm, the detector can realize the electrons’ collection efficiency of 46.3% and the electrons’ gain of 1570. The induced circuit pulse of avalanche electrons is about 16ns. Good gain and time characteristics indicate the detector has a good application prospect

Keywords: Micro-Pattern Gaseous Detectors, PPGEM, Avalanche
12:30 PM N-06-04

Small-Strip Thin Gap Chambers Integration and Commissioning for ATLAS NSW Phase-I Upgrade (#367)

P. Atmasiddha1

1 University of Michigan,, Department of Physics, Ann Arbor, Michigan, United States of America

On behalf of the ATLAS Muon Collaboration


The Large Hadron Collider (LHC) will reach an instantaneous luminosity of up to 5 − 7.5 × 10^34cm−2s−1. This necessitates the upgrade of the muon spectrometer of the ATLAS detector. The Small Wheel, the innermost station of muon end-cap system, will be replaced by the ’New Small Wheel (NSW)’. The new system is required to improve trigger selectivity for the end-cap region in a high background environment. To accomplish this, it should deliver 1 mrad angular resolution, 150 μm spatial resolution and a trigger latency within 1 μs. This is achieved by two detector technologies, Small-Strip Thin Gas Chamber (sTGC) and Micro Mesh Gaseous structures (MM). sTGC is the primary trigger detector because of its bunch crossing identification capability. Along with this state of the art detector technology, radiation tolerant custom-made ASICs are built to create high-speed data inter-connections, which achieve up to 1 MHz of Level-1 data readout using the Back-End FELIX (Front End LInk eXchange) system. This complex system of ∼400K physical channels and more than ∼14K ASICs creates many challenges, which include achieving precise alignment of the readout channels for high spatial resolution and maintain simultaneous trigger and readout with a background rate of ∼ 20kHzcm−2. sTGC detector quadruplets are assembled and aligned into wedges at CERN. We summarize the design requirements, description of the detector system and our experiences during the sTGC integration and commissioning of the detector. These detector studies are performed for the first time together with the final Front-End and Back-End electronics. Our work includes alignment survey of the detector channels, establishing proper connectivity between the detector and the Front-End channels, verifying the robustness of the detector performance against various noise sources, while tuning numerous clock phases and delays for synchronous readout at high rate.

Keywords: ATLAS Muon Spectrometer, sTGC
12:45 PM N-06-05

Performance of the new Readout Electronics for the ATLAS (s)MDT Chambers and Future Colliders at High Background Rates (#445)

G. Eberwein1, H. Kroha1, O. Kortner1, E. Voevodina1

1 Max-Planck-Institute for Physics, Munich, Bavaria, Germany


Small-diameter Drift Tube (sMDT) detectors with 15 mm tube diameter have proven to be excellent candidates for precision muon tracking detectors in experiments at future hadron colliders like HL-LHC and FCC-hh where unprecedentedly high background rate capabilities are required. sMDT chambers are currently being installed in the inner barrel layer of the ATLAS muon spectrometer. The rate capability of the sMDT drift tubes in terms of muon detection efficiency and spatial resolution is limited by the performance of the readout electronics. A new (s)MDT ASD (Amplifier-Shaper-Discriminator) readout chip for use at the HL-LHC and future hadron colliders with a faster peaking time compared to the old chip has been developed, reducing the discriminator threshold crossing time jitter and thus improving the time- and spatial resolution with and without γ-background radiation. Additionally, a method compensating the gas gain drop due to space charge at high γ-background hit flux by adjusting the sMDT operating voltage will be presented. Simulations show, that the addition of active baseline restoration circuits in the front-end electronics chips in order to suppress signal-pile-up effects at high counting rates further leads to significant improvement of both efficiency and resolution. Extensive tests using sMDT test chambers have been performed at the CERN Gamma Irradiation Facility (GIF++). Chambers equipped with new readout chips with improved pulse shaping and discrete readout circuits with baseline restoring functionality have been tested. Results of both simulation and test will be presented.

Keywords: ATLAS, FCC, muon system, position sensitive particle detectors, sMDT drift tube detectors
1:00 PM N-06-06

Upgrade of the CMS Muon System for the High Luminosity LHC (#1276)

C. Aruta1

1 University and INFN, Bari, Italy


In view of the High Luminosity phase of the Large Hadron Collider (HL-LHC), which is expected to deliver an instantaneous luminosity 5 times higher with respect to the present value, the muon spectrometer of the CMS experiment will undergo specific upgrades targeting both the detectors and the electronics with the goal to cope with the new challenging data-taking conditions and to improve the present tracking and triggering capabilities. The detector upgrades will mainly concern the deployment of new stations based on triple gas electron multiplier (GEM) and improved resistive plate chambers (iRPC) technology. The new stations, featuring improved time and spatial resolution and enhanced rate capability, will be installed in the endcap of the muon system, where the background rate is expected to be higher. Nevertheless, the simulation study demonstrates that the new stations will allow to reach higher efficiencies with a modest background rate delivered at the first trigger level. The upgrade of the electronics will target instead the present system, based on drift tubes (DT), cathode strip chambers (CSC) and RPC. Radiation-hard components, extensively tested at the Gamma Irradiation Facility (GIF++), will be installed on those detectors operating since 2008. This contribution will describe the upgrades of the different subsystems of the CMS muon spectrometer; we will report the results of the CSC electronics upgrade, the first performance of the new electronics of the DTs, assessed during the Run 2 slice test and the aging test performed on both. The production, qualification and installation of a first station based on triple-GEM detectors (GE1/1) and the first results of its commissioning will be described along with an overview of the design, R&D and first performance of new stations based on triple-GEM (GE2/1, ME0) and iRPC detectors (RE3/1 and RE4/1) that will be installed around 2023.

Keywords: muon system, gaseous detectors, CMS, LHC, upgrade
1:15 PM N-06-07

R&D strategies for optimizing the greenhouse gas consumption at the CERN LHC experiments (#382)

R. Guida1, M. Corbetta1, B. Mandelli1, G. Rigoletti2

1 CERN, EP, Geneva, Switzerland
2 Universite Claude Bernard Lyon I, Physics, Lyon, France


A wide range of gas mixtures is used for the operation of different gaseous detectors for particle physics research. Among them are greenhouse gases like C2H2F4 (R134a), CF4 (R14), C4F10 (R610) and SF6, which are used because they allow to achieve specific detector performance that are necessary for data taking at the LHC experiments (i.e. stability, long term performance, time resolution, rate capability, etc.). Such gases are currently subject to a phase down policy that started to affect the market with price increase and, in the long term, may cause a decrease in their availability. Four different strategies have been identified to optimize the gas usage. As immediate actions, during the LHC Long Shutdown 2 the gas systems will be upgraded to cope with new detector requirements and, in parallel, extensive campaigns for fixing leaks at detector level will be performed. The development of gas recuperation plants is going to be the next step. They aim in extracting greenhouse gases from the exhaust of gas recirculation systems allowing further re-use. Several plants of this type are already in use. Recent developments are concerning a system for R134a recuperation. For future long-term detector operation, R&D studies are ongoing for finding green alternatives to the currently used gases (especially for R134a). The last strategy consists in the possibility of using industrially developed plants for the disposal of greenhouse gases by decomposition in harmless compounds. This solution avoids the emission in the atmosphere, but it is not optimizing the gas usage and problems like gas availability and price for detector operation might become the challenge in the coming years due to the greenhouse phase down policy.

The four R&D strategies were fully launched in 2019. This contribution will review status and achievements for gas system optimization and greenhouse gas recuperation.

Keywords: gaseous detectors, gas systems, gas recuperation, greenhouse gas, environmentally friendly gas
1:30 PM N-06-08

MPGD-based photon detectors of single photon from COMPASS towards EIC (#1389)

S. S. Dasgupta1

1 INFN Trieste, Detector Development Lab, Trieste, Italy


In 2016, COMPASS RICH (Ring Imaging CHerenkov) photo-detection plane was upgraded with novel gaseous photon detectors based on MPGD technology: four novel Photon Detectors (PD), covering a total active area of 1.5 square m, cope with the challenging efficiency and stability requirements of the COMPASS physics programme. The detector architecture consists in a hybrid MPGD architecturte: two layers of THGEMs, the first of which also acts as a reflective PC thanks to CsI coating, are coupled to a bulk resistive Micromegas on a pad-segmented anode; the signals are read-out by analog F-E based on the APV-25 chip. These detectors are the first application in an experiment of MPGD-based single photon detectors. A RICH detector for hadron identification at the future Electron Ion Collider (EIC) is needed for high momentum range. A compact collider setup imposes a RICH with a short radiator length, hence limiting the number of photons, which can be increased by choosing a far UV region. COMPASS-like detectors with increased space resolution are being developed for this application. Moreover, an R&D for a novel and robust photo-cathode (PC) material based on hydrogenated nanodiamond particles for gaseous PDs has been initiated. The first phase of these studies includes the characterization of THGEMs coated with nanodiamont PC, the comparison of the effective QE in vacuum and in gaseous atmospheres and the aging effects by ion bombardment. The approach is described in detail as well as all the results obtained so far with these exploratory studies.

AcknowledgmentThis R&D activity is partially supported by
• EU Horizon 2020 research and innovation programme, STRONG-2020 project, under grant agreement No 824093;
EU Horizon 2020 research and innovation programme, AIDAinnova project, under grant agreement No 101004761;
• the Program Detector Generic R&D for an Electron Ion Collider by Brookhaven National Laboratory, in association with Jefferson Lab and the DOE Office of Nuclear Physics.
Keywords: RICH, MPGD, Photon Detectors, THGEM, PID

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