Heidelberg 2015 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 62: Nuclear Astrophysics 5

HK 62.1: Group Report

Thursday, March 26, 2015, 17:00–17:30, P/H1

The COBRA experiment - Status report — •Thomas Quante for the COBRA collaboration — Technische Universität Dortmund, Otto-Hahn-straße 4, 44221 Dortmund

COBRA is a next-generation experiment searching for neutrinoless double beta (0νββ) decay using CdZnTe semiconductor detectors. The main focus is on 116Cd, with a Q-value of 2813.5 keV well above the highest naturally occurring gamma lines. By measuring the half-life of the 0νββ decay, it is possible to clarify the nature of the neutrino as either Dirac or Majorana particle and furthermore to determine the effective Majorana mass.

For this purpose a detector array made up of 64 Cadmium-Zinc-Telluride (CdZnTe) semiconductor detectors in coplanar grid configuration was designed and realised at the Gran Sasso Underground laboratory (LNGS) in Italy. It is used to gather information about the long term stability in low background operation and the identification of potential background components.

Simulations of the whole demonstrator setup are ongoing to reproduce the measured spectra for each detector. As the "detector=source" principle, the 0nbb signal can happen all over the detector. Therefore, events that occur on the detector surface are most likely background events. The pulse shape analysis gives the opportunity to reject these events, which lowers the the overall background in the region of interest by more than one order of magnitude. In this talk an overview of the detector technology and analysis techniques is given. In addition the recent progress and future plans will be discussed.