Author/Authors :
Levin، نويسنده , , Daniel S. and Amram، نويسنده , , Nir and Ball، نويسنده , , Robert and ben Moshe، نويسنده , , Meny and Benhammou، نويسنده , , Yan and Chapman، نويسنده , , John W. and Dai، نويسنده , , Tiesheng and Diehl، نويسنده , , Edward B. and Etzion، نويسنده , , Erez and Ferretti، نويسنده , , Claudio and Goldfarb، نويسنده , , Steven and Gregory، نويسنده , , Jeffery and Kiesel، نويسنده , , Mike and McKee، نويسنده , , Shawn and Thun، نويسنده , , Rudi and Weaverdyck، نويسنده , , Curtis and Wilson، نويسنده , , Alan and Zhao، نويسنده , , Zhengguo and Zhou، نويسنده , , Bing، نويسنده ,
Abstract :
The ATLAS Muon Spectrometer incorporates 354 000 drift tubes assembled into 1200 Monitored Drift Tube (MDT) precision chambers, with a total gas volume of 723 m 3 . This MDT gas, Ar 93% and CO 2 7% at 3 bar, is cycled through the spectrometer at a rate of one total detector volume per day. Achieving the 80 μ m drift tube design resolution requires stringent gas quality control as a fundamental component of the MDT calibration program. We report on the design, deployment and performance of a dedicated MDT mini-chamber conceived for continuous monitoring and drift time calibration of the ATLAS MDT operating gas. This chamber enables measurement of the drift spectra from which gas properties relevant to MDT calibrations and stable operating conditions are determined. Located in the ATLAS gas facility at CERN, the mini-chamber produces hourly drift spectra which are automatically analyzed. Results are published online and disseminated to the ATLAS muon system conditions and calibration databases in real time.
Keywords :
Calibration , Drift tube , RT function , DRIFT spectra , TDC spectra , Time-to-space , Gas monitoring , Muon chamber
