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T: Fachverband Teilchenphysik
T 65: Niederenergie-Neutrinophysik 3
T 65.2: Talk
Tuesday, March 25, 2014, 17:05–17:20, P106
Setup for an in-situ measurement of the total light extinction of liquid argon in GERDA — •Birgit Schneider for the GERDA collaboration — IKTP, TU Dresden, Deutschland
The Germanium Detector Array (GERDA) is an experiment searching for neutrinoless double beta decay in 76Ge. The observation of such a decay would prove the Majorana character of the neutrino and could provide a hint about the neutrino mass and possibly identify the mass hierarchy scheme. GERDA uses germanium detectors which are enriched in 76Ge and operates them naked in liquid argon (LAr), which serves both as a coolant and a shield for external radiation. Phase I of GERDA ended after one and a half year of measurement, in May 2013, with an exposure of 21.6 kg · yr and a background index (BI) of 10−2 cts/(kg · yr · keV), after applying pulse shape discrimination techniques. For Phase II it is planned to reach an exposure of 100 kg · yr with a BI of 10−3 cts/(kg · yr · keV). One of the key improvements to further reduce the BI is to instrument the LAr to act as an additional background veto. The light extinction of the scintillation light of LAr is a key feature to characterize the LAr instrumentation. It is very dependent on the impurities in the liquid and is needed to determine the effective active LAr veto volume. The work shall include the construction of a setup for such an in-situ measurement as well as the measurement itself. This involves the development of a setup design, the selection of the materials and components such as the calibration source and the photomultiplier with the related electronic parts. In this talk a status report of the activities and results will be presented.