Münster 2017 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 12: Neutrinophysik 2 (Doppelbetazerfall)

T 12.8: Vortrag

Montag, 27. März 2017, 18:35–18:50, VSH 118

Background characterization in Gerda Phase II — •Ann-Kathrin Schütz for the GERDA collaboration — Eberhard Karls Universität Tübingen, Germany

The Gerda collaboration aims to determine the half-life of the neutrinoless double beta decay (0νββ) of ⁷⁶Ge. In Phase II additional 20 kg of isotopically enriched germanium detectors are operated. To further increase the sensitivity for the half-life of neutrinoless double beta decay the identification and suppression of the background is of great importance. The application of active background-suppression techniques, such as a liquid argon scintillation light read-out and pulse shape discrimination of germanium detector signals allowed to reduce the background index to the intended level of 10⁻³ cts/(keV·kg·yr). The background components at Q_{β β} have been identified to be mainly due to β- and γ-induced events from close sources originating from the U-series, the Th-series, K and α emitting isotopes from the ²²⁶Ra decay chain. (Anti-)coincidences between germanium detectors and with the liquid argon veto enlarges the tools of identification compared to Phase I. A background study based on results of material screening or the observation of characteristic structures in the energy spectrum was performed and will be presented in this talk.