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The European Physical Journal C

, 75:506

First Online: 27 October 2015Received: 22 January 2015Accepted: 17 September 2015

Abstract

LArGe is a Gerda low-background test facility to study novel background suppression methods in a low-background environment, for future application in the Gerda experiment. Similar to Gerda, LArGe operates bare germanium detectors submersed into liquid argon 1 m\^3\, 1.4 tons, which in addition is instrumented with photomultipliers to detect argon scintillation light. The scintillation signals are used in anti-coincidence with the germanium detectors to effectively suppress background events that deposit energy in the liquid argon. The background suppression efficiency was studied in combination with a pulse shape discrimination PSD technique using a BEGe detector for various sources, which represent characteristic backgrounds to Gerda. Suppression factors of a few times \10^3\ have been achieved. First background data of LArGe with a coaxial HPGe detector without PSD yield a background index of 0.12\-\4.6\\times 10^{-2}\ cts-keV kg year 90 % C.L., which is at the level of Gerda Phase I. Furthermore, for the first time we monitor the natural \^{42}\Ar abundance parallel to Gerda, and have indication for the \2 u \beta \beta \-decay in natural germanium. These results show the effectivity of an active liquid argon veto in an ultra-low background environment. As a consequence, the implementation of a liquid argon veto in Gerda Phase II is pursued.

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Author: M. Agostini - M. Barnabé-Heider - D. Budjáš - C. Cattadori - A. Gangapshev - K. Gusev - M. Heisel - M. Junker - A. Kli

Source: https://link.springer.com/



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