Mainz 2014 – scientific programme

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T: Fachverband Teilchenphysik

T 18: Niederenergie-Neutrinophysik 1

T 18.3: Talk

Monday, March 24, 2014, 11:30–11:45, P106

Single-site and Multi-site Event Discrimination for the COBRA Experiment — •Stefan Zatschler for the COBRA collaboration — IKTP, TU Dresden, Germany

The aim of the COBRA experiment is to prove the existence of neutrinoless double beta decay for several isotopes intrinsically abundant in the detector material. Currently a demonstrator setup built of 64 coplanar grid detectors collects high quality low background physics data at the underground laboratory LNGS (Italy). The detectors are made of cadmium zinc telluride, which is a commercially available room temperature semiconductor material.
One of the key instruments to further reduce background is to identify so called multi-site events (MSE) via pulse shape analysis. MSEs are typically caused by multiply-scattered highly energetic photons. Since the energy deposition of a 0νββ event is expected to be almost always single-site, all events of the same energy clearly identified as MSEs can be rejected.
In this talk a lab experiment is presented that makes use of Compton scattering to verify the signal efficiency of the newly developed SSE/MSE cuts. Furthermore, the application of the algorithms is tested on physics data to identify the contribution of multi-site events to the total background of the COBRA experiment.