24,967 research outputs found
Data and figures for Characterization of 30 ^{76}Ge enriched Broad Energy Ge detectors for GERDA Phase II
No full textData and figures for Characterization of 30 76Ge enriched Broad Energy Ge detectors for GERDA Phase II</p
An improved limit on the neutrinoless double-electron capture of 36 Ar with GERDA
No full textAbstract The GERmanium Detector Array (Gerda) experiment operated enriched high-purity germanium detectors in a liquid argon cryostat, which contains 0.33% of 36 Ar, a candidate isotope for the two-neutrino double-electron capture (2 ν ECEC) and therefore for the neutrinoless double-electron capture (0 ν ECEC). If detected, this process would give evidence of lepton number violation and the Majorana nature of neutrinos. In the radiative 0 ν ECEC of 36 Ar, a monochromatic photon is emitted with an energy of 429.88 keV, which may be detected by the Gerda germanium detectors. We searched for the 36 Ar 0 ν ECEC with Gerda data, with a total live time of 4.34 year (3.08 year accumulated during Gerda Phase II and 1.26 year during Gerda Phase I). No signal was found and a 90% CL lower limit on the half-life of this process was established T 1 / 2 > 1.5 · 10 22 year
Status of the GERDA Experiment
No full textThe GERDA experiment is being built in the LNGS underground laboratories for the search for neutrinoless double beta decay. Phase I of the experiment GERDA will be able to test the claim of observation of the neutrinoless double beta decay. In a second phase newly developed detectors will be added aiming to a total exposure of 100 kg yr. Status of the experiment and first results from segmented detectors operated in cryogenic liquid are presented.JRC.D.4 - Nuclear physic
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Background-free search for neutrinoless double-β decay of 76Ge with GERDA.
No full textMany extensions of the Standard Model of particle physics explain the dominance of matter over antimatter in our Universe by neutrinos being their own antiparticles. This would imply the existence of neutrinoless double-β decay, which is an extremely rare lepton-number-violating radioactive decay process whose detection requires the utmost background suppression. Among the programmes that aim to detect this decay, the GERDA Collaboration is searching for neutrinoless double-β decay of 76Ge by operating bare detectors, made of germanium with an enriched 76Ge fraction, in liquid argon. After having completed Phase I of data taking, we have recently launched Phase II. Here we report that in GERDA Phase II we have achieved a background level of approximately 10-3 counts keV-1 kg-1 yr-1. This implies that the experiment is background-free, even when increasing the exposure up to design level. This is achieved by use of an active veto system, superior germanium detector energy resolution and improved background recognition of our new detectors. No signal of neutrinoless double-β decay was found when Phase I and Phase II data were combined, and we deduce a lower-limit half-life of 5.3 × 1025 years at the 90 per cent confidence level. Our half-life sensitivity of 4.0 × 1025 years is competitive with the best experiments that use a substantially larger isotope mass. The potential of an essentially background-free search for neutrinoless double-β decay will facilitate a larger germanium experiment with sensitivity levels that will bring us closer to clarifying whether neutrinos are their own antiparticles
The GERDA Experiment: Search for the Neutrinoless Double Beta Decay
No full textThe Germanium Detector Array (Gerda) experiment is searching for the neutrinoless double beta decay of Ge. The observation of this Beyond the Standard Model process would prove the existence of a neutrino Majorana mass component and provide information on the neutrino mass hierarchy and absolute mass scale. {\sc Gerda} operates enriched germanium diodes, acting simultaneously as the source and detector material, directly submerged in liquid argon. Phase I achieved the world's best lower limit of ~yr (90\% C.L.). With the recent completion of the upgrade to Phase II, an additional 20~kg of germanium detectors -- for a total of 35~kg -- and a liquid argon veto system have been implemented. The goal is an order of magnitude lower background with a projected sensitivity of ~yr for
The GERDA Experiment in the Search for Neutrinoless Double-Beta Decay
No full textAn open question still involves the nature of neutrinos: are they equal to their anti-matter counterpart? The most promising way to test this Majorana nature of neutrinos is searching for the neutrinoless double beta decay (0 nu beta beta), a hypothetical lepton number violating nuclear process. Furthermore, its observation would give an extraordinary insight into why our universe is predominantly composed of matter, which is another unsolved puzzle of cosmology and particle physics. Since 2011, the Gerda collaboration has searched for 0 nu beta beta of Ge-76 by operating bare germanium detectors, enriched in the double-beta decaying isotope Ge-76, in liquid argon. Exploiting the combination of excellent energy resolution of germanium detectors and scintillating properties of argon, the Gerda experiment succeeded to achieve an unprecedented background-free regime. In December 2019, after fulfilling and exceeding the design goals of the experiment, data taking was stopped. No signal has been observed, hence a lower limit on the half-life of 0 nu beta beta in Ge-76 has been set at T-1/2(0 nu) > 1.8 x 10(26) years at 90% C.L. The final results of the 12 Gerda experiment are discussed
Calibration of the Gerda experiment
No full textThe GERmanium Detector Array (Gerda) collaboration searched for neutrinoless double-β decay in 76Ge with an array of about 40 high-purity isotopically-enriched germanium detectors. The experimental signature of the decay is a monoenergetic signal at Qββ =2039.061(7) keV in the measured summed energy spectrum of the two emitted electrons. Both the energy reconstruction and resolution of the germanium detectors are crucial to separate a potential signal from various backgrounds, such as neutrino-accompanied double-β decays allowed by the Standard Model. The energy resolution and stability were determined and monitored as a function of time using data from regular 228Th calibrations. In this work, we describe the calibration process and associated data analysis of the full Gerda dataset, tailored to preserve the excellent resolution of the individual germanium detectors when combining data over several years
The GERmanium Detector Array (Gerda) for the search of neutrinoless ββ decays of 76Ge at LNGS
No full textThis paper describes the proposed Gerda experiment, the GERmanium Detector Array for the search of neutrinoless ββ decays of 76Ge at LNGS. The goal of the Gerda project is to operate bare germanium diodes enriched in 76Ge in an (optional active) cryogenic fluid shield with a sensitivity for neutrinoless ββ decay of T1/2>21026 years after an exposure of 100 kg years
Improvement of the energy resolution via an optimized digital signal processing in GERDA Phase I
No full textAn optimized digital shaping filter has been developed for the Gerda experiment which searches for neutrinoless double beta decay in Ge. The Gerda Phase I energy calibration data have been reprocessed and an average improvement of 0.3 keV in energy resolution (FWHM) corresponding to 10 % at the value for decay in Ge is obtained. This is possible thanks to the enhanced low-frequency noise rejection of this Zero Area Cusp (ZAC) signal shaping filter.Peer Reviewe
The Structure of Scientific Collaboration Networks in Scientometrics
No full textThe structure of scientific collaboration networks in scientometrics was investigated at the level of individuals by using bibliographic data of all papers published in the international journal Scientometrics retrieved from the Science Citation Index (SCI) during 1978 to 2004. Combined analysis of social network analysis (SNA), co-occurrence analysis, cluster analysis and frequency analysis of words was explored to reveal: (1) The microstructure of the collaboration network on scientists’ aspects of scientometrics; (2) The major collaborative fields of the collaborative sub-networks; (3) The collaborative center of the collaboration network in scientometrics
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