摘要：The ATLAS New Small Wheel (NSW) is a major phase-1 upgrade of the Muon system, completed in 2022.  The goal is to equip the muon spectrometer with a new sub-detector, which allows the system to operate at much higher instantaneous luminosity than the initial design value (high luminosity HL-LHC). It consists of new detector technologies, resistive Micromegas and small strip Thin Gap Chambers, as well as a number of dedicated ASICS.  The conception of NSW date back to the time shortly after the start of LHC data taking. Two main factors, observation of unexpected source of background in the muon trigger, and projected hit occupancy at the HL-LHC condition, eventually converged to the idea of a new detector that solves the two issues altogether. In the presentation, I will discuss in some detail the observation and interpretation of the nature of background particles, followed by historical account of the process of detector technology choice, construction and installation.  The status of the performance achievement is finally summarized.

报告人简介：

1981 : PhD from Hiroshima University, Japan
1981: JSPS fellow, Japan
1982: Researcher at the University of Tokyo
1994: Associate Professor, ICEPP the University of Tokyo
2019: Conseiller Scientifique, CEA Saclay IRFU, University of Paris-Saclay
2023: International visiting professor, USTC

Main activities
JADE experiment at PETRA e+e- collider at DESY Hamburg. 
OPAL experiment at LEP e+e- collider at CERN.
ATLAS experiment at LHC hadron collider at CERN.