Wuppertal 2015 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 41: Detektoren und DAQ 1
T 41.1: Vortrag
Dienstag, 10. März 2015, 16:45–17:00, G.10.07 (HS 5)
Purity control system of the Liquid Argon calorimeter of the ATLAS experiment — •Maurice Becker, Stefan Tapprogge, and Ulrich Schaefer — Johannes Gutenberg-Universität Mainz
At the ATLAS detector (LHC at CERN) a Liquid Argon calorimeter is used to precisely measure the energy of the electromagnetic interacting particles. Particles deposit their energy in the calorimeter by creating a particle shower. The ionization of the Liquid-Argon due to the shower particles can be used to determine the energy of the initial particle. Possible electronegative impurities in the calorimeter could reduce the ionization which would lead to a worse energy resolution. In order to monitor the purity of the Liquid-Argon several purity monitors are distributed over the calorimeter. Each monitor consists of a ionization chamber with two radioactive sources (241Am and 207Bi). The decay particles of the probes create a certain, known amount of charge carrier that are collected by applying an electromagnetic field. The measurement of the signal amplitude from these charge carriers can be used to measure the purity of the Liquid Argon. This talk gives an overview of the system with a focus of a new implementation of a OPC-UA server that reads out the monitors and determines the purity values. In addition results on the long term stability of the purity will be shown.