D. Lomidze

The CMS RPC gas gain monitoring system: An Overview and preliminary results

The status of the Compact Solenoid Spectrometer (CMS) Resistive Plate Counter (RPC) Gas Gain Monitoring (GGM) system developed at the Frascati Laboratory of INFN (Istituto Nazionale di Fisica Nucleare) is reported. The GGM system is a cosmic ray telescope based on small RPC detectors operated with the same gas mixture used by the CMS RPC system. The GGM gain and efficiency are continuously monitored on-line, thus providing a fast and accurate determination of any shift in working point conditions. The construction details and the first result of GGM commissioning are described.

Sensitivity and environmental response of the CMS RPC Gas Gain Monitoring system

Results from the gas gain monitoring (GGM) system for the muon detector using RPC in the CMS experiment at the LHC is presented. The system is designed to provide fast and accurate determination of any shift in the working point of the chambers due to gas mixture changes.

Sensitivity and environmental response of the CMS RPC gas gain monitoring system

Results from the gas gain monitoring (GGM) system for the muon detector using RPC in the CMS experiment at the LHC is presented. The system is designed to provide fast and accurate determination of any shift in the working point of the chambers due to gas mixture changes.

Radiation tests of real-sized prototype RPCs for the Phase-2 Upgrade of the CMS Muon System

We report on a systematic study of double-gap and four-gap phenolic resistive plate chambers (RPCs) for future high-{\eta} RPC triggers in the CMS. 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 for cosmic rays and 100 GeV muons provided by the SPS H4 beam line at CERN. We applied maximum gamma rates of 1.5 kHz cm-2 provided by 137Cs sources at Korea University and the GIF++ irradiation facility installed at the SPS H4 beam line to examine the rate capabilities of the prototype RPCs. In contrast to the case of the four-gap RPCs, we found the relatively high threshold 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 LHC runs.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 Cs-137 sources providing maximum gamma rates of about 1.5 kHz cm(-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).

R&D towards the CMS RPC Phase-2 upgrade

The high pseudo-rapidity region of the CMS muon system is covered by Cathode Strip Chambers (CSC) only and lacks redundant coverage despite the fact that it is a challenging region for muons in terms of backgrounds and momentum resolution. In order to maintain good efficiency for the muon trigger in this region additional RPCs are planned to be installed in the two outermost stations at low angle named RE3/1 and RE4/1. These stations will use RPCs with finer granularity and good timing resolution to mitigate background effects and to increase the redundancy of the system.

Detector control system and efficiency performance for CMS RPC at GIF

In the framework of the High Luminosity LHC upgrade program, the CMS muon group built several different RPC prototypes that are now under test at the new CERN Gamma Irradiation Facility (GIF++). A dedicated Detector Control System (DCS) has been developed using the WinCC-OA tool to control and monitor these prototype detectors and to store the measured parameters data. Preliminary efficiency studies that set the base performance measurements of CMS RPC for starting aging studies are also presented.