Münster 2017 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 12: Neutrinophysik 2 (Doppelbetazerfall)
T 12.7: Vortrag
Montag, 27. März 2017, 18:20–18:35, VSH 118
In-situ measurement of the light attenuation in liquid argon in the Gerda cryostat — •Birgit Schneider for the GERDA collaboration — TU Dresden, Institut für Kern- und Teilchenphysik, Germany
Gerda is an experiment searching for the neutrinoless double beta decay in 76Ge. It operates the enriched germanium detectors bare in liquid argon (LAr), which serves both as a coolant and a shield for external radiation. Phase II of Gerda aims for an exposure of 100 kg · yr with a background index (BI) of 10−3 cts/(kg · yr · keV). One of the major improvements compared to Phase I is the instrumentation of the LAr to readout its scintillation light to further reduce the BI. Recently, first results of Phase II were published which have shown that the aimed BI could be reached. Hence, Gerda is operating quasi background-free and has the lowest background ever achieved with Ge-based 0νββ-experiments. The attenuation of the scintillation light in LAr limits the effective active volume of the LAr veto and is therefore a key parameter to characterize the instrumentation.
In order to measure the light attenuation in LAr, a setup was designed that could be deployed directly into the cryostat. This setup contains a movable beta source and a PMT to detect the scintillation light at different distances.
The talk will present the acquired data as well as a detailed description of the performed analysis, the results and a comparison with a dedicated simulation.
This project is partially funded by BMBF.