R&D on the Resistive Plate Chamber for the Phase-II Upgrade of the CMS Muon Detector

The Doctoral Thesis subject has been proposed by the CMS RPC Collaboration to demonstrate that iRPC technology is the most suitable choice for the upgrade of the Muon System. The next research activities have been conducted in this context: The first activity, conducted in the framework of the iRPC RE3/1 and RE4/1 chambers integration and installation in the innermost region of CMS Muon Spectrometer, is focused on survey measurements performed in order to determine the space actually available for future installations during the Yearly Technical Stops at the end of 2022 and 2023. Surface topology and geometry of the Yoke Endcap (YE) ±2 and YE±3 iron disks in the region 1.8<|eta|<2.4 have been studied in detail by using different methods such as photography, photogrammetry, theodolite and infrared proximity sensor. After analyzing the experimental data obtained during the survey measurements, I developed the very precise 3D-model of the mechanical simulation for the installation of the RE3/1 and RE4/1 detectors in the dedicated |eta| region. I designed the mechanical components to mount chambers here. These results of my work were reported in the CMS Muon Technical Design Report (TDR) which was submitted to the CMS Muon Committee on 12 September 2017. The second activity has been focused on the developing, commissioning and characterization of the iRPC RE3/1 and RE4/1 detector prototypes. By using the information obtained during the previous activity, in August 2017 at the CERN CMS-RPC QA/QC facility, I organized the development and assembly of the first two real-size RE3/1 and RE4/1 detector prototypes and studied their detection performance with the new version of the PETIROC ASIC Front-end electronics. I was the key person who participated in all production processes on the construction and testing the detecting elements, assembling of the new prototypes and subsequent testing them with the new electronics under muon beam at the CERN Gamma Irradiation Facility (GIF++) in August 2018. By using the unique test area of the CERN GIF++ facility, I studied the iRPC detector performances at the different background conditions which will be similar to the future CMS conditions during the HL-LHC program. By studying the rate capability of the real-size iRPC detector prototypes I have experimentally shown that the new iRPC technology can effectively operate in the harsh background CMS environmental and can fulfill all physics requirements of the CMS experiment. The third my activity included the testing of the new INFN Rome Front-end electronics together with iRPC detector prototype. The INFN Rome electronics has been proposed as a possible alternative to PETIROC ASIC electronics in time for the CMS-RPC system upgrade project, thus increasing the chance of success for the project. This has been the main strategy adopted by the CMS-RPC community and, consequently, it was necessary to find another available technology in order to develop the Front-end electronics to readout the iRPC detectors. In September 2018, I developed and assembled the second real-size iRPC RE4/1 detector prototype in the INFN Rome Tor Vergata laboratories (Italy) in order to study the performance with the INFN Rome Front-end boards. As in the previous research activity, I organized the subsequent testing of the iRPC detector prototype with the new electronics in the last available muon particle beam in the GIF++ facility at CERN before the starting of the Long Shutdown -2 period at LHC. In order to compare the results obtained from the first two RE3/1 and RE4/1 detector prototypes, I have studied the same number of chamber parameters of second iRPC RE4/1 detector prototype, such as a detection efficiency, cluster size, and rate capability. I experimental shown that this type of new Front-end board can be a great substitute for the PETIROC ASIC electronics. A majority of the results obtained during the last two years of Ph.D. contributed to the success of the iRPC project and its final approval by CMS Collaboration.