The Study Of The Front-End Electronics For The Small-strip Thin Gap Chambers Of The ATLAS New-Small-Wheel Upgrade

In 2012,CERN announced that the ATLAS and CMS experiments on its Large Hadron Collider discovered the Higgs boson simultaneously.This important discoverydirectly won the 2013 Nobel Prize in Physics.The next scientific goal of the entire LHC experiment is to measure the Higgs boson accurately while looking for new particles and new phenomena beyond the standard model.To achieve this ambitious scientific goal,the entire LHC will be upgraded to be the High-Luminosity LHC(HL-LHC),with the luminosity increased from 1×1034cm-2s-1 to 7×1034cm-2s-1.This HL-LHC is expected to go online after 2026.The ATLAS experiment at CERN is scheduled to replace the innermost station of its Muon Spectrometer in the forward region during its Phase-I upgrade in order to enhance the capabilities on triggering and tracking of high transverse momentum muons towards high luminosity LHC runs.The New Small Wheel(NSW),a completely new detector system to be built,is composed of two novel gaseous detectors:Micro-mesh Gaseous Structure(Micromegas)and the small-strip Thin Gap Chamber(sTGC).The sTGC sub-system is the primary trigger detector.It will be equipped with radiation-tolerant,low-latency electronics for reading out over 400,000 channels to identify the bunch crossing time of proton-proton collisions spaced by 25 ns,as well as to collect fine strip charge information for the charged track reconstruction.In this paper,we present the design and development of a set of Front-End Boards(FEBs)for the sTGC detector system.The major challenges in the design will be discussed.These include the accommodation of a few hundred readout channels per single board in a very constrained space,a tight requirement for the ESD protection of 130 nm AISCs,and customized analog input circuits to handle the high rate and high charge signals from the sTGC detectors.Moreover,the FEBs have to incorporate a few hundred parallel inter-chip links at 320 Mbps and several low-latency serial links operating at 4.8 Gbps for the Level-1 and trigger data readout.In this paper,thetest requirements of the Front-End electronics validation will be analyzed,and the design of the test system prepared for the sTGC Front-End Boards will be introduced.Meanwhile,this paperwill introduce in detail all the tests for the sTGC Front-End Boards,including the electronics tests,the detector tests,and the system integration tests.The characterization of the FEBs performance,both off-detector and on-detector,will be shown.All the test results show that the design of the sTGC Front-End Electronics is successful and will surely meet the needs from the NSW sTGCsystem.The main innovations of this paper are as follows:(1)The design and development ofthe sTGC Front-End Boards,a high-density,high-precision,low-noisefront-end electronics system for the NSW sTGC detectors,is successfully completed.The design of the sTGC Front-End Board is an all-in-one solution,withall the necessary functions such as analog amplification,digitization,triggering,and high-speed communication integratedon a single board.The maximum number of channels per front-end board can reach 512 channels,the maximumtrigger rate is up to 1MHzper channel,and the equivalent noise charge is less than 1fC.Thesecharacterizes make the sTGC Front-End Boardsalmost the best front-end electronics system for the similar gas detectors at home and abroad.(2)A new type of high-efficiency and low-noise power supply is designed and implemented,which successfully solves the technical problem that high efficiency and low noise are difficult to achieve under high power consumption.Its noise level is only 180?VRMS,far more quiet than common commercial solutions.Based on this new power supply module,the noise level of the sTGC Front-End Boards is successfully controlled under 1fC ENC.(3)It is the first time to successfully integrate the sTGC Front-End Boards with all the different sized NSW sTGC detectors.The sTGC Front-End system,with over 400,000 channels and 1MHz trigger capacity,provides the possibility for the ATLAS Muon Spectrometer to operate with the HL-LHC,and will certainlycontributeto the study of the God particle.