Dresden 2013 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 105: Suche nach Dunkler Materie 1
T 105.4: Vortrag
Montag, 4. März 2013, 11:50–12:05, HSZ-103
Simulation of Sputtered Ions as Background for the CRESST-Experiment — •Stephan Scholl — Technische Universität München, James-Franck Strasse 1, 85743 Garching
The results of GEANT4 simulations regarding the background contribution induced by 210Po decays in the clamps holding the detector crystals in the CRESST–II experiment are presented. Particles produced in the wake of such a decay deposit energy (≤ 100 keV) in the detector crystal which cannot be vetoed if the α particle from the decay is absorbed in the non–scintillating clamp. Since detector hits at energies below 40 keV are a background to the CRESST–II Dark Matter search, the spectral shape of the energy deposition has to be inferred from a suitable reference region. The energy distribution of the sputtered ions and the simulataneously measured scintillation light has been modeled with simulation tools to relate the number of particles in the acceptance region to the number of events seen in a suitable reference region. Recent studies have shown that this ratio critically depends on the surface roughness of the contaminated material. However, only the distribution in deposited energy but not in the lightyield has been investigated and only generic surface roughnesses were considered. In this contribution, we show simulations indicating that the induced background in the signal region within the deposited energy – scintillation light plane exceeds the one hithero assumed for the measured experimental surface roughness and for suitable parameters of implantation depth of 210 Po.