JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - UNPB AU - Fiorina, D. ED - Furukawa, Kazuro ED - Yan, Yingbing ED - Leng, Yongbin ED - Chen, Zhichu ED - Schaa, Volker R.W. TI - The GEM Gas Monitoring System: Using a Gaseous Detector as a Gas Detector for CMS Triple-GEM Safe Operation J2 - Proc. of ICALEPCS2021, Shanghai, China, 14-22 October 2021 CY - Shanghai, China T2 - International Conference on Accelerator and Large Experimental Physics Control Systems T3 - 18 LA - english AB - The CMS experiment will exploit the Gas Electron Multiplier (GEM) technology for the first time during the next LHC run. Maintain the gas mixture quality and concentration is fundamental for the safe and correct operation of such gaseous detectors. An Ar concentration 1% higher or lower will respectively increase or decrease the detector gain of almost 15%. The CMS GEM Group decided to develop a monitoring system of the gas concentration by exploiting a small Triple-GEM detector. The gain measurement of this test chamber, fed by the gas mixture derived from the CMS GEM gas system, allows retrieving information about the Ar/CO₂ ratio. Detection of wrong gas concentrations in the test chamber will allow to trigger warnings or alarms before sending the gas to the GEM detectors and eventually to real-time tune the working point. This contribution will describe the GEM Gas Monitoring system from the design to the commissioning foreseen for end 2021. It will report about the calibration procedure, illustrating all the necessary steps to detect gain changes of around 5% corresponding to a systematic variation of Argon (or CO₂) concentration of 0.33%. PB - JACoW Publishing CP - Geneva, Switzerland ER -