Based on previous experience and attempt, a real-size mosaic Multi-gap Resistive Plate Chamber (MRPC) has been developed within the framework of the CMS muon upgrade efforts. The chamber is a 5-gap ...with plates made each of 6 pieces of low resistive glass. Cosmic ray test at CERN 904 shows that its efficiency can reach above 95% with a gas mixture of 90% C2H2F4, 5% i-C4H10 and 5% SF6. The chamber was also tested with CMS dry gas(95.2% C2H2F4, 4.5% i-C4H10, 0.3% SF6) at the CERN Gamma Irradiation Facility (GIF++). Efficiency results calculated by a simple tracking method show that the good performance is maintained at rates up to 10 kHz/cm2.
This paper introduces a novel production technique for the planar wire grid plates of microstrip gas chambers (MSGCs, gaseous particle detectors), taking advantage from the typical thin film ...metallization technologies. The aim of the work here presented has been to manufacture MSGC substrates which can meet the challenging requirements proper to particle tracking detectors in highly ionizing environments. These requirements are mainly represented by high reliability and robustness, since the devices are supposed to operate efficiently for at least 10 years in the extremely hostile conditions foreseen at the large hadron collider at CERN (CH). A detailed process description will be given and results will be analyzed both from the production point of view and from the application of the manufactured prototypes as detectors for high energy physics experiments.
The CMS experiment comprises MSGCs as one of the key detection elements for high luminosity tracking at LHC. In _addition to the high dose rate of 10 mC/year per cm of strip, these detectors have to ...survive the hostile presence of highly ionizing particles, neutrons low energy gammas and hadrons. In this report we present the results of systematic tests on maximum safe operational gain limits in MSGCs before the discharge. Long term ageing tests performed on prototype open ‘banana’ modules envisaged to be arranged around the interaction region in the forward part of the CMS tracker show no evidence of gain drop up to equivalent ∼ 10 years of LHC operation. A comparison is made between argon and neon gas mixtures with DME in equal proportions by investigating long term irradiation effocts on chamber operation by introducing controlled and reproducible pollution in the gas lines.
Test of a CMS MSGC tracker prototype in a high-intensity hadron beam Abbaneo, D.; Albert, E.; Angelini, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1998, Letnik:
409, Številka:
1-3
Journal Article
Recenzirano
A set of CMS MicroStrip Gas Chambers (MSGC) was exposed to a high-intensity 3GeV/c pion beam at a CERN PS facility for a period of two weeks. The performance of the detectors is reported in terms of ...stability of efficiency and response to minimum ionising particles as well as to more heavily ionising fragments generated by nuclear interactions.
The RPC muon detector of the CMS experiment at the LHC (CERN, Geneva, Switzerland) is equipped with a Gas Gain Monitoring (GGM) system. A report on the stability of the system during the 2011-2012 ...data taking run is given, as well as the observation of an effect which suggests a novel method for the monitoring of gas mixture composition.
We report on a systematic study of double-gap and four-gap phenolic resistive plate chambers (RPCs) for the Phase-2 upgrade of the CMS muon system at high eta. In the present study, we constructed ...real-sized double-gap and four-gap RPCs with gap thicknesses of 1.6 and 0.8 mm, respectively, with 2-mm-thick phenolic high-pressure-laminated (HPL) plates. We examined the prototype RPCs with cosmic rays and with 100-GeV muons provided by the SPS H4 beam line at CERN. To examine the rate capability of the prototype RPCs both at Korea University and at the CERN GIF++ facility, the chambers were irradiated with super(137) Cs sources providing maximum gamma rates of about 1.5 kHz cm super(?2). For the 1.6-mm-thick double-gap RPCs, we found the relatively high threshold on the produced detector charge was conducive to effectively suppressing the rapid increase of strip cluster sizes of muon hits with high voltage, especially when measuring the narrow-pitch strips. The gamma-induced currents drawn in the four-gap RPC were about one-fourth of those drawn in the double-gap RPC. The rate capabilities of both RPC types, proven through the present testing using gamma-ray sources, far exceeded the maximum rate expected in the new high-eta endcap RPCs planned for future phase-II runs of the Large Hadron Collider (LHC).
Development of RE1/1 RPCs for the CMS muon trigger system Park, S.; Ahn, S.H.; Akimenko, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2009, Letnik:
602, Številka:
3
Journal Article
Recenzirano
The first six Resistive Plate Chambers (RPCs) of RE1/1 in the forward region of the Compact Muon Solenoid (CMS) detector were constructed and are being tested. These RPCs cover the pseudo-rapidity ...region from 1.6 to 2.1 and will serve as the base detector for the CMS RPC muon trigger. We report that these six RPCs are being tested with the CMS RPC quality certification procedures and that a full measurement of a chamber efficiency of
95
±
4
%
has been achieved at an operating voltage of 9.4
kV. This performance demonstrates that the RPC is qualified to be tested at the closest distance to the beam pipe as the muon trigger detector at the full LHC design luminosity.
A search for pair-production of first generation scalar leptoquarks is performed in the final state containing an electron, a neutrino, and at least two jets using proton-proton collision data at ...inline image. The data were collected by the CMS detector at the LHC, corresponding to an integrated luminosity of 36 pb super(-1. The number of observed events is in good agreement with the predictions for standard model processes. Prior CMS results in the dielectron channel are combined with this electron + neutrino search. A 95% confidence level combined lower limit is set on the mass of a first generation scalar leptoquark at 339 GeV for beta=0.5, where beta is the branching fraction of the leptoquark to an electron and a quark. These results represent the most stringent direct limits to date for values of beta greater than 0.05.)
A measurement of the ratio of the inclusive 3-jet to 2-jet cross sections as a function of the total jet transverse momentum, H sub(T), in the range 0.2<H sub(T)<2.5 TeV is presented. The data have ...been collected at a proton-proton centre-of-mass energy of 7 TeV with the CMS detector at the LHC, and correspond to an integrated luminosity of 36 pb super(-1). Comparisons are made between the data and the predictions of different QCD-based Monte Carlo models for multijet production. All models considered in this study are consistent with the data for H sub(T)>0.5 TeV. This measurement extends to an H sub(T) range that has not been explored before.
A measurement of W gamma and Z gamma production in proton-proton collisions at inline imageinline image is presented. Results are based on a data sample recorded by the CMS experiment at the LHC, ...corresponding to an integrated luminosity of 36 pb super(-1. The electron and muon decay channels of the W and Z are used. The total cross sections are measured for photon transverse energy inline imageinline image and spatial separation from charged leptons in the plane of pseudorapidity and azimuthal angle Delta R(l, gamma )0.7, and with an additional dilepton invariant mass requirement of M) sub(l)l50 GeV for the Z gamma process. The following cross section times branching fraction values are found: inline imageinline image and inline imageinline image. These measurements are in agreement with standard model predictions. The first limits on anomalous WW gamma , ZZ gamma , and Z gamma gamma trilinear gauge couplings at inline imageinline image are set.
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