5,166 research outputs found
CMS endcap RPC gas gap production for upgrade
The CMS experiment will install a RE4 layer of 144 new Resistive Plate Chambers (RPCs) on the existing york YE3 at both endcap regions to trigger high momentum muons from the proton-proton interaction. In this paper, we present the detailed procedures used in the production of new RPC gas gaps adopted in the CMS upgrade. Quality assurance is enforced as ways to maintain the same quality of RPC gas gaps as the existing 432 endcap RPC chambers that have been operational since the beginning of the LHC operation
Performance of the Gas Gain Monitoring system of the CMS RPC muon detector and effective working point fine tuning
The Gas Gain Monitoring (GGM) system of the Resistive Plate Chamber (RPC)
muon detector in the Compact Muon Solenoid (CMS) experiment provides fast and
accurate determination of the stability in the working point conditions due to
gas mixture changes in the closed loop recirculation system. In 2011 the GGM
began to operate using a feedback algorithm to control the applied voltage, in
order to keep the GGM response insensitive to environmental temperature and
atmospheric pressure variations. Recent results are presented on the feedback
method used and on alternative algorithms
The Upgrade of the CMS RPC System during the First LHC Long Shutdown
The CMS muon system includes in both the barrel and endcap region Resistive
Plate Chambers (RPC). They mainly serve as trigger detectors and also improve
the reconstruction of muon parameters. Over the years, the instantaneous
luminosity of the Large Hadron Collider gradually increases. During the LHC
Phase 1 (~first 10 years of operation) an ultimate luminosity is expected above
its design value of 10^34/cm^2/s at 14 TeV. To prepare the machine and also the
experiments for this, two long shutdown periods are scheduled for 2013-2014 and
2018-2019. The CMS Collaboration is planning several detector upgrades during
these long shutdowns. In particular, the muon detection system should be able
to maintain a low-pT threshold for an efficient Level-1 Muon Trigger at high
particle rates. One of the measures to ensure this, is to extend the present
RPC system with the addition of a 4th layer in both endcap regions. During the
first long shutdown, these two new stations will be equipped in the region
|eta|<1.6 with 144 High Pressure Laminate (HPL) double-gap RPCs operating in
avalanche mode, with a similar design as the existing CMS endcap chambers.
Here, we present the upgrade plans for the CMS RPC system for the fist long
shutdown, including trigger simulation studies for the extended system, and
details on the new HPL production, the chamber assembly and the quality control
procedures.Comment: 9 pages, 6 figures, presented by M.Tytgat at the XI workshop on
Resistive Plate Chambers and Related Detectors (RPC2012), INFN - Laboratori
Nazionali di Frascati, February 5-10, 201
Simulation of the CMS Resistive Plate Chambers
The Resistive Plate Chamber (RPC) muon subsystem contributes significantly to
the formation of the trigger decision and reconstruction of the muon trajectory
parameters. Simulation of the RPC response is a crucial part of the entire CMS
Monte Carlo software and directly influences the final physical results. An
algorithm based on the parametrization of RPC efficiency, noise, cluster size
and timing for every strip has been developed. Experimental data obtained from
cosmic and proton-proton collisions at TeV have been used for
determination of the parameters. A dedicated validation procedure has been
developed. A good agreement between the simulated and experimental data has
been achieved.Comment: to be published in JINS
High rate, fast timing Glass RPC for the high {\eta} CMS muon detectors
The HL-LHC phase is designed to increase by an order of magnitude the amount
of data to be collected by the LHC experiments. To achieve this goal in a
reasonable time scale the instantaneous luminosity would also increase by an
order of magnitude up to . The region of the forward
muon spectrometer () is not equipped with RPC stations. The
increase of the expected particles rate up to (including a
safety factor 3) motivates the installation of RPC chambers to guarantee
redundancy with the CSC chambers already present. The actual RPC technology of
CMS cannot sustain the expected background level. The new technology that will
be chosen should have a high rate capability and provides a good spatial and
timing resolution. A new generation of Glass-RPC (GRPC) using low-resistivity
(LR) glass is proposed to equip at least the two most far away of the four high
muon stations of CMS. First the design of small size prototypes and
studies of their performance in high-rate particles flux is presented. Then the
proposed designs for large size chambers and their fast-timing electronic
readout are examined and preliminary results are provided.Comment: 14 pages, 11 figures, Conference proceeding for the 2016 Resistive
Plate Chambers and Related Detector
Tests of multigap RPCs for high-eta triggers in CMS
In this paper, we report a systematic study of multigap Resistive Plate Chambers (RPCs) for high-eta triggers in CMS. Prototype RPC modules with four- and six-gap structures have been constructed with phenolic high-pressure-laminated (HPL) plates and tested with cosmic muons and gamma rays irradiated from a 200-mCi Cs-137 source. The detector characteristics of the prototype multigap RPCs were compared with those of the double-gap RPCs currently used in the CMS experiment at LHC. The mean values for detector charges of cosmic-muon signals drawn in the four- and six-gap RPCs for the efficiency values in the middle of the plateau were about 1.5 and 0.9 pC, respectively, when digitized with charge thresholds of 150 and 100 fC, respectively. They were respectively about one third and one fifth of that drawn in the current CMS double-gap RPC with a charge threshold of 200 fC. We concluded from the current R&D that use of the current phenolic-HPL multigap RPCs is advantageous to the high-eta triggers in CMS in virtue of the smaller detector pulses
Overview of large area triple-GEM detectors for the CMS forward muon upgrade
In order to cope with the harsh environment expected from the high luminosity LHC, the CMS forward muon system requires an upgrade. The two main challenges expected in this environment are an increase in the trigger rate and increased background radiation leading to a potential degradation of the particle ID performance. Additionally, upgrades to other subdetectors of CMS allow for extended coverage for particle tracking, and adding muon system coverage to this region will further enhance the performance of CMS
A novel application of Fiber Bragg Grating (FBG) sensors in MPGD
We present a novel application of Fiber Bragg Grating (FBG) sensors in the
construction and characterisation of Micro Pattern Gaseous Detector (MPGD),
with particular attention to the realisation of the largest triple (Gas
electron Multiplier) GEM chambers so far operated, the GE1/1 chambers of the
CMS experiment at LHC. The GE1/1 CMS project consists of 144 GEM chambers of
about 0.5 m2 active area each, employing three GEM foils per chamber, to be
installed in the forward region of the CMS endcap during the long shutdown of
LHC in 2108-2019. The large active area of each GE1/1 chamber consists of GEM
foils that are mechanically stretched in order to secure their flatness and the
consequent uniform performance of the GE1/1 chamber across its whole active
surface. So far FBGs have been used in high energy physics mainly as high
precision positioning and re-positioning sensors and as low cost, easy to
mount, low space consuming temperature sensors. FBGs are also commonly used for
very precise strain measurements in material studies. In this work we present a
novel use of FBGs as flatness and mechanical tensioning sensors applied to the
wide GEM foils of the GE1/1 chambers. A network of FBG sensors have been used
to determine the optimal mechanical tension applied and to characterise the
mechanical tension that should be applied to the foils. We discuss the results
of the test done on a full-sized GE1/1 final prototype, the studies done to
fully characterise the GEM material, how this information was used to define a
standard assembly procedure and possible future developments.Comment: 4 pages, 4 figures, presented by Luigi Benussi at MPGD 2015 (Trieste,
Italy). arXiv admin note: text overlap with arXiv:1512.0848
Charged particle detection performance of Gas Electron Multiplier (GEM) detectors for the upgrade of CMS endcap muon system at the CERN LHC
The Compact Muon Solenoid (CMS) detector is one of the two general-purpose detectors at the CERN LHC. LHC will provide exceptional high instantaneous and integrated luminosity after second long shutdown. The forward region |η| ≥ 1:5 of CMS detector will face extremely high particle rates in tens of kHz/cm2 and hence it will affect the momentum resolution, efficiency and longevity of the muon detectors. Here, η is pseudorapidity defined as η = -ln(tan(θ/2)), where θ is the polar angle measured from z-axis. To overcome these issues the CMSGEM 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 (1:6 <; |η| <; 2.2) of the muon endcap during the long shutdown 2 (LS2) of the LHC. Towards this goal, full size CMS Triple GEM detectors have been fabricated and tested at the CERN SPS, H2 and H4 test beam facility. The GEM detectors were operated with two gas mixtures: Ar/CO2 (70/30) and Ar/CO2/CF4 (45/15/40). In 2014, good quality data was collected during test beam campaigns. In this paper, the performance of the detectors is summarized based on their tracking efficiency and time resolution
Development and performance of Triple-GEM detectors for the upgrade of the muon system of the CMS experiment
The CMS Collaboration is evaluating GEM detectors for the upgrade of the muon system. This contribution will focus on the R&D performed on chambers design features and will discuss the performance of the upgraded detector
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