scholarly journals RESULTS ON NEUTRINOLESS DOUBLE-BETA DECAY FROM GERDA PHASE I

2014 ◽  
Vol 29 (01) ◽  
pp. 1430001 ◽  
Author(s):  
CARLA MACOLINO ◽  
Keyword(s):  
Energy Spectrum ◽  
Phase I ◽  
Beta Decay ◽  
Half Life ◽  
Pulse Shape ◽  
Germanium Detector ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Recent Claim ◽  
Detection Principle

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.

GERDA results and the future perspectives for the neutrinoless double beta decay search using 76Ge

2018 ◽  
Vol 33 (09) ◽  
pp. 1843004 ◽  
Author(s):  
◽  
M. Agostini ◽  
A. M. Bakalyarov ◽  
M. Balata ◽  
I. Barabanov ◽  
...  
Keyword(s):  
Phase I ◽  
Beta Decay ◽  
Phase Ii ◽  
Half Life ◽  
Liquid Argon ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Second Phase ◽  
Inverted Hierarchy ◽  
Phase Phase

The GERmanium Detector Array (GERDA) is a low background experiment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN designed to search for the rare neutrinoless double beta decay ([Formula: see text]) of [Formula: see text]Ge. In the first phase (Phase I) of the experiment, high purity germanium diodes were operated in a “bare” mode and immersed in liquid argon. The overall background level of [Formula: see text] was a factor of ten better than those of its predecessors. No signal was found and a lower limit was set on the half-life for the [Formula: see text] decay of [Formula: see text]Ge [Formula: see text] yr (90% CL), while the corresponding median sensitivity was [Formula: see text] yr (90% CL). A second phase (Phase II) started at the end of 2015 after a major upgrade. Thanks to the increased detector mass and performance of the enriched germanium diodes and due to the introduction of liquid argon instrumentation techniques, it was possible to reduce the background down to [Formula: see text]. After analyzing 23.2 kg[Formula: see text]⋅[Formula: see text]yr of these new data no signal was seen. Combining these with the data from Phase I a stronger half-life limit of the [Formula: see text]Ge [Formula: see text] decay was obtained: [Formula: see text] yr (90% CL), reaching a sensitivity of [Formula: see text] yr (90% CL). Phase II will continue for the collection of an exposure of 100 kg[Formula: see text]yr. If no signal is found by then the GERDA sensitivity will have reached [Formula: see text] yr for setting a 90% CL. limit. After the end of GERDA Phase II, the flagship experiment for the search of [Formula: see text] decay of [Formula: see text]Ge will be LEGEND. LEGEND experiment is foreseen to deploy up to 1-ton of [Formula: see text]Ge. After ten years of data taking, it will reach a sensitivity beyond 10[Formula: see text] yr, and hence fully cover the inverted hierarchy region.

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

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.

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

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
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.).

scholarly journals Results from the Cuore Experiment †

Universe ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 10 ◽  
Author(s):  
Alessio Caminata ◽  
Douglas Adams ◽  
Chris Alduino ◽  
Krystal Alfonso ◽  
Frank Avignone ◽  
...  
Keyword(s):  
Beta Decay ◽  
Energy Resolution ◽  
Half Life ◽  
Precise Measurement ◽  
Region Of Interest ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Effective Energy ◽  
Β Decay ◽  
Compact Structure

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO 2 crystals arranged in a cylindrical compact structure of 19 towers, each of them made of 52 crystals. The construction of the experiment was completed in August 2016 and the data taking started in spring 2017 after a period of commissioning and tests. In this work we present the neutrinoless double beta decay results of CUORE from examining a total TeO 2 exposure of 86.3 kg yr , characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts / ( keV kg yr ) . In this physics run, CUORE placed a lower limit on the decay half-life of neutrinoless double beta decay of 130 Te > 1.3 · 10 25 yr (90% C.L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130 Te 2 ν β β decay with a resulting half-life of T 1 / 2 2 ν = [ 7.9 ± 0.1 ( stat . ) ± 0.2 ( syst . ) ] × 10 20 yr which is the most precise measurement of the half-life and compatible with previous results.

scholarly journals Searching for Neutrinoless Double-Beta Decay of130Te with CUORE

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
D. R. Artusa ◽  
F. T. Avignone ◽  
O. Azzolini ◽  
M. Balata ◽  
T. I. Banks ◽  
...  
Keyword(s):  
Beta Decay ◽  
Energy Resolution ◽  
Confidence Level ◽  
Half Life ◽  
Average Energy ◽  
Neutrinoless Double Beta Decay ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Current Status ◽  
Upper Limit

Neutrinoless double-beta (0νββ) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0νββdecay of130Te using an array of 988 TeO2crystal bolometers operated at 10 mK. The detector will contain 206 kg of130Te and have an average energy resolution of 5 keV; the projected 0νββdecay half-life sensitivity after five years of livetime is 1.6 × 1026 y at 1σ(9.5 × 1025 y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40–100 meV (50–130 meV). In this paper, we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach.

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