CERN Accelerating science

CMS Note
Report number	CMS-CR-2019-211
Title	Readout and Trigger Electronics for the Triple-GEM Detectors of the CMS GE2/1 System
Author(s)	Matveev, Mikhail (Rice U.)
Publication	2019
Collaboration	CMS Collaboration
Imprint	11 Oct 2019
Number of pages	6
Presented at	TWEPP 2019 Topical Workshop on Electronics for Particle Physics, Santiago De Compostela, Spain, 2 - 6 Sep 2019
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; CMS
Keywords	Muons
Abstract	The Triple Gas Electron Multiplication (GEM) technology has been adopted for the upgrade of the forward muon detector system at the CMS experiment for the future High-Luminosity phase of the Large Hadron Collider (LHC) at CERN. The GE2/1 subdetector comprises 72 chambers that will be installed after the second LHC Long Shutdown. The GE2/1 chambers are segmented in 4 modules with 12 sectors in each module, and each sector is composed of 128 radial strips. The strips are read out by the front-end VFAT3 ASIC. It has 128 channels, each with a charge sensitive preamplifier, shaper and a discriminator. Each module is equipped with the OptoHybrid (OH) board that provides the readout and trigger interfaces for 12 VFAT3 ASICs. The OH board uses CERN designed GigaBit Transceivers (GBT) for the readout path. VFAT3 ASICs also provide trigger information that allows the OH to build trigger clusters using the Xilinx Artix-7 FPGA and to transmit this cluster data the back-end Trigger Processor and to the local Cathode Strip Chamber Trigger Motherboard to improve local trigger efficiency at an early stage of the trigger processing. The back-end electronics will use the ATCA Trigger Processor farm; it will send the data to the Endcap Muon Track Finder and to the CMS DAQ system. In this presentation, we report on progress on the GE2/1 electronics and results from the first demonstrator tests performed at CERN in 2019, and we outline our future design and production plans.