https://doi.org/10.1140/epjc/s10052-022-10163-w
Regular Article - Experimental Physics
Pulse shape analysis in Gerda Phase II
1
INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi, Italy
2
INFN Laboratori Nazionali del Gran Sasso and Università degli Studi dell’Aquila, L’Aquila, Italy
3
INFN Laboratori Nazionali del Sud, Catania, Italy
4
Institute of Physics, Jagiellonian University, Cracow, Poland
5
Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden, Germany
6
Joint Institute for Nuclear Research, Dubna, Russia
7
European Commission, JRC-Geel, Geel, Belgium
8
Max-Planck-Institut für Kernphysik, Heidelberg, Germany
9
Department of Physics and Astronomy, University College London, London, UK
10
Dipartimento di Fisica, Università Milano Bicocca, Milan, Italy
11
INFN Milano Bicocca, Milan, Italy
12
Dipartimento di Fisica, Università degli Studi di Milano and INFN Milano, Milan, Italy
13
Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, Russia
14
Institute for Theoretical and Experimental Physics, NRC “Kurchatov Institute”, Moscow, Russia
15
National Research Centre “Kurchatov Institute”, Moscow, Russia
16
Max-Planck-Institut für Physik, Munich, Germany
17
Physik Department, Technische Universität München, Munich, Germany
18
Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Padua, Italy
19
INFN Padova, Padua, Italy
20
Physikalisches Institut, Eberhard Karls Universität Tübingen, Tübingen, Germany
21
Physik-Institut, Universität Zürich, Zurich, Switzerland
22
NRNU MEPhI, Moscow, Russia
23
Moscow Inst. of Physics and Technology, Moscow, Russia
24
Dubna State University, Dubna, Russia
25
Institut für Experimentelle Teilchenphysik, Karlsruher Institut für Technologie, Karlsruhe, Germany
26
Robert Bosch GmbH, Stuttgart, Germany
27
Nuclear Science Division, Berkeley, USA
28
Physik Department, Technische Universität München, Munich, Germany
Received:
5
November
2021
Accepted:
23
February
2022
Published online:
1
April
2022
The GERmanium Detector Array (Gerda) collaboration searched for neutrinoless double- decay in
Ge using isotopically enriched high purity germanium detectors at the Laboratori Nazionali del Gran Sasso of INFN. After Phase I (2011–2013), the experiment benefited from several upgrades, including an additional active veto based on LAr instrumentation and a significant increase of mass by point-contact germanium detectors that improved the half-life sensitivity of Phase II (2015–2019) by an order of magnitude. At the core of the background mitigation strategy, the analysis of the time profile of individual pulses provides a powerful topological discrimination of signal-like and background-like events. Data from regular
Th calibrations and physics data were both considered in the evaluation of the pulse shape discrimination performance. In this work, we describe the various methods applied to the data collected in Gerda Phase II corresponding to an exposure of 103.7 kg year. These methods suppress the background by a factor of about 5 in the region of interest around
keV, while preserving
% of the signal. In addition, an exhaustive list of parameters is provided which were used in the final data analysis.
E. Bellotti: deceased.
© The Author(s) 2022
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