Search for neutrinoless double beta decay of Ge-76 with the GERmanium Detector Array "GERDA"

The GERmanium Detector Array, GERDA, is designed to search for neutrinoless double-beta (0νββ) decay of 76 Ge and it is installed in the Laboratori Nazionali del Gran Sasso (LNGS) of INFN, Italy. In this review, the detection principle and detector setup of GERDA are described. Also, the main physics results by GERDA Phase I, are discussed. They include the measurement of the half-life of 2νββ decay, the background decomposition of the energy spectrum and the techniques for the discrimination of the background, based on the pulse shape of the signal. In the last part of this review, the estimation of a limit on the half-life of 0νββ ([Formula: see text] at 90% C.L.) and the comparison with previous results are discussed. GERDA data from Phase I strongly disfavor the recent claim of 0νββ discovery, based on data from the Heidelberg–Moscow experiment.

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Fabrication, characterization and analysis of a prototype high purity germanium detector for $$^{76}$$Ge-based neutrinoless double beta decay experiments

The European Physical Journal C ◽

10.1140/epjc/s10052-020-08781-3 ◽

2021 ◽

Vol 81 (1) ◽

Author(s):

A. Jany ◽

M. Misiaszek ◽

T. Mroz ◽

K. Panas ◽

G. Zuzel ◽

...

Keyword(s):

Beta Decay ◽

Pulse Shape ◽

Germanium Detector ◽

Background Level ◽

Neutrinoless Double Beta Decay ◽

Double Beta Decay ◽

Pulse Shape Discrimination ◽

Discovery Potential ◽

Excellent Energy Resolution ◽

Prototype Detector

AbstractExperiments searching for the neutrinoless double beta decay in $$^{76}$$ 76 Ge are currently achieving the lowest background level and, in connection with the excellent energy resolution of germanium detectors, they exhibit the best discovery potential for the decay. Expansion to a ton scale of the active target mass is presently considered – in this case on-site production of the detectors may be an option. In this paper we describe the fabrication and characterization procedures of a prototype detector with a small p+ contact, which enhances the abilities of the pulse shape discrimination – one of the most important tools for background reduction. Simulations of the shapes of pulses from the detector were carried out and tuned, taking the advantage of the fact that all the parameters of the Ge crystal, cryostat and of the spectroscopic chain were known. As a result, the pulse shape analyses performed on the simulated and measured data agree very well. The worked out method allows to optimize geometry and crystal parameters in terms of pulse shape analysis efficiency, before the actual production of the detectors.

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Status of the GERDA Experiment at the Laboratori Nazionali del Gran Sasso

Advances in High Energy Physics ◽

10.1155/2013/506186 ◽

2013 ◽

Vol 2013 ◽

pp. 1-15 ◽

Cited By ~ 6

Author(s):

R. Brugnera ◽

A. Garfagnini

Keyword(s):

Beta Decay ◽

High Purity ◽

Pulse Shape ◽

Germanium Detector ◽

Liquid Argon ◽

Neutrinoless Double Beta Decay ◽

Double Beta Decay ◽

Second Phase ◽

High Purity Germanium ◽

Better Than

The Germanium Detector Array (Gerda) is a low background experiment at the Laboratori Nazionali del Gran Sasso (LNGS) of the INFN designed to search for the rare neutrinoless double beta decay (0νββ) of76Ge. In its first phase, high purity germanium diodes inherited from the former Heidelberg-Moscow and Igexexperiments are operated “bare” and immersed in liquid argon, with an overall background environment of 10−2 cts/(keV·kg·yr), a factor of ten better than its predecessors. Measurements on two-neutrino double beta decay (2νββ) givingT1/22ν=(1.88±0.10)×1021 yrand recently published background model and pulse shape performances of the detectors are discussed in the paper. A new result on0νββhas been recently published with a half-life limit on0νββdecayT1/20ν>2.1×1025 yr(90% C.L.). A second phase of the experiment is scheduled to start during the year 2014, after a major upgrade shutdown. Thanks to the increased detector mass with new designed diodes and to the introduction of liquid argon instrumentation techniques, the experiment aims to reduce further the expected background to about 10−3 cts/(keV·kg·yr) and to improve the0νββsensitivity to aboutT1/20ν>1.5×1026 yr(90% C.L.).

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