Dresden 2013 – scientific programme

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T: Fachverband Teilchenphysik

T 110: Experimentelle Techniken der Astroteilchenphysik 3

T 110.3: Talk

Tuesday, March 5, 2013, 17:20–17:35, HSZ-101

Dead Layer and Active Volume Determination for GERDA Phase II Detectors — •Bjoern Lehnert — TU Dresden, Dresden, Germany

The GERDA experiment investigates the neutrinoless double beta decay of ⁷⁶Ge and is currently running Phase I of its physics program. Using the same isotope as the Heidelberg Moscow (HDM) experiment, GERDA aims to directly test the claim of observation by a subset of the HDM collaboration. For the update to Phase II of the experiment in 2013, the collaboration organized the production of 30 new Broad Energy Germanium (BEGe) type detectors from original 35kg enriched material and tested their performance in the low background laboratory HADES in SCK·CEN, Belgium. With additional 20kg of detectors, GERDA aims to probe the degenerated hierarchy scenario.

One of the crucial detector parameters is the active volume (AV) fraction which directly enters into all physics analysis. This talk presents the methodology of dead layer and AV determination with different calibration sources such as ²⁴¹Am, ¹³³Ba, ⁶⁰Co and ²²⁸Th and the results obtained for the new Phase II detectors. Furthermore, the AV fraction turned out to be the largest systematic uncertainty in the analysis of Phase I data which makes it imperative to reduce its uncertainty for Phase II. This talk will address the major contributions to the AV uncertainty and gives an outlook for improvements in Phase II analysis.

This work is funded by the BMBF and supported by the HPC, ZIH Dresden.