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Search Results: 1 - 10 of 84401 matches for " W. Maneschg "
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Highly Sensitive Gamma-Spectrometers of GERDA for Material Screening: Part 2
D. Budjá?,W. Hampel,M. Heisel,G. Heusser,M. Keillor,M. Laubenstein,W. Maneschg,G. Rugel,S. Sch?nert,H. Simgen,H. Strecker
Physics , 2008,
Abstract: The previous article about material screening for GERDA points out the importance of strict material screening and selection for radioimpurities as a key to meet the aspired background levels of the GERDA experiment. This is directly done using low-level gamma-spectroscopy. In order to provide sufficient selective power in the mBq/kg range and below, the employed gamma-spectrometers themselves have to meet strict material requirements, and make use of an elaborate shielding system. This article gives an account of the setup of two such spectrometers. Corrado is located in a depth of 15 m w.e. at the MPI-K in Heidelberg (Germany), GeMPI III is situated at the Gran-Sasso underground laboratory at 3500 m w.e. (Italy). The latter one aims at detecting sample activities of the order ~0.01 mBq/kg, which is the current state-of-the-art level. The applied techniques to meet the respective needs are discussed and demonstrated by experimental results.
Production and characterization of a custom-made 228Th source with reduced neutron source strength for the Borexino experiment
W. Maneschg,L. Baudis,R. Dressler,K. Eberhardt,R. Eichler,H. Keller,R. Lackner,B. Praast,R. Santorelli,J. Schreiner,M. Tarka,B. Wiegel,A. Zimbal
Physics , 2011, DOI: 10.1016/j.nima.2012.04.019
Abstract: A custom-made 228Th source of several MBq activity was produced for the Borexino experiment for studying the external background of the detector. The aim was to reduce the unwanted neutron emission produced via (alpha,n) reactions in ceramics used typically for commercial 228Th sources. For this purpose a ThCl4 solution was converted chemically into ThO2 and embedded into a gold foil. The paper describes the production and the characterization of the custom-made source by means of gamma-activity, dose rate and neutron source strength measurements. From gamma-spectroscopic measurements it was deduced that the activity transfer from the initial solution to the final source was >91% (at 68% C.L.) and the final activity was (5.41+-0.30) MBq. The dose rate was measured by two dosimeters yielding 12.1 mSv/h and 14.3 mSv/h in 1 cm distance. The neutron source strength of the 5.41 MBq 228Th source was determined as (6.59+-0.85)/sec.
Highly sensitive gamma-spectrometers of GERDA for material screening: Part I
D. Budjá?,C. Cattadori,A. Gangapshev,W. Hampel,M. Heisel,G. Heusser,M. Hult,A. Klimenko,V. Kuzminov,M. Laubenstein,W. Maneschg,S. Nisi,S. Sch?nert,H. Simgen,A. Smolnikov,C. Tomei,A. di Vacri,S. Vasiliev,G. Zuzel
Physics , 2008,
Abstract: The GERDA experiment aims to search for the neutrinoless double beta-decay of 76Ge and possibly for other rare processes. The sensitivity of the first phase is envisioned to be more than one order of magnitude better than in previous neutrinoless double beta-decay experiments. This implies that materials with ultra-low radioactive contamination need to be used for the construction of the detector and its shielding. Therefore the requirements on material screening include high-sensitivity low-background detection techniques and long measurement times. In this article, an overview of material-screening laboratories available to the GERDA collaboration is given, with emphasis on the gamma-spectrometry. Additionally, results of an intercomparison of the evaluation accuracy in these laboratories are presented.
Statistical Analysis of future Neutrino Mass Experiments including Neutrino-less Double Beta Decay
Maneschg, Werner;Merle, Alexander;Rodejohann, Werner
High Energy Physics - Phenomenology , 2008, DOI: 10.1209/0295-5075/85/51002
Abstract: We perform a statistical analysis with the prospective results of future experiments on neutrino-less double beta decay, direct searches for neutrino mass (KATRIN) and cosmological observations. Realistic errors are used and the nuclear matrix element uncertainty for neutrino-less double beta decay is also taken into account. Three benchmark scenarios are introduced, corresponding to quasi-degenerate, inverse hierarchical neutrinos, and an intermediate case. We investigate to what extend these scenarios can be reconstructed. Furthermore, we check the compatibility of the scenarios with the claimed evidence of neutrino-less double beta decay.
HEROICA: an Underground Facility for the Fast Screening of Germanium Detectors
E. Andreotti,A. Garfagnini,W. Maneschg,N. Barros,G. Benato,R. Brugnera,F. Costa,R. Falkenstein,K. K. Guthikonda,A. Hegai,S. Hemmer,M. Hult,K. Jaenner,T. Kihm,B. Lehnert,H. Liao,A. Lubashevskiy,G. Lutter,G. Marissens,L. Modenese,L. Pandola,M. Reissfelder,C. Sada,M. Salathe,C. Schmitt,O. Schulz,B. Schwingenheuer,M. Turcato,C. Ur,K. von Sturm,V. Wagner,J. Westermann
Physics , 2013, DOI: 10.1088/1748-0221/8/06/P06012
Abstract: An infrastructure to characterize germanium detectors has been designed and constructed at the HADES Underground Research Laboratory, located in Mol (Belgium). Thanks to the 223m overburden of clay and sand, the muon flux is lowered by four orders of magnitude. This natural shield minimizes the exposure of radio-pure germanium material to cosmic radiation resulting in a significant suppression of cosmogenic activation in the germanium detectors. The project has been strongly motivated by a special production of germanium detectors for the GERDA experiment. GERDA, currently collecting data at the Laboratori Nazionali del Gran Sasso of INFN, is searching for the neutrinoless double beta decay of 76Ge. In the near future, GERDA will increase its mass and sensitivity by adding new Broad Energy Germanium (BEGe) detectors. The production of the BEGe detectors is done at Canberra in Olen (Belgium), located about 30km from the underground test site. Therefore, HADES is used both for storage of the crystals over night, during diode production, and for the characterization measurements. A full quality control chain has been setup and tested on the first seven prototype detectors delivered by the manufacturer at the beginning of 2012. The screening capabilities demonstrate that the installed setup fulfills a fast and complete set of measurements on the diodes and it can be seen as a general test facility for the fast screening of high purity germanium detectors. The results are of major importance for a future massive production and characterization chain of germanium diodes foreseen for a possible next generation 1-tonne double beta decay experiment with 76Ge.
GIOVE - A New Detector Setup for High Sensitivity Germanium Spectroscopy At Shallow Depth
Gerd Heusser,Marc Weber,Janina Hakenmüller,Matthias Laubenstein,Manfred Lindner,Werner Maneschg,Hardy Simgen,Dominik Stolzenburg,Herbert Strecker
Physics , 2015,
Abstract: We report on the development and construction of the high-purity germanium spectrometer setup GIOVE (Germanium Inner Outer Veto), recently built and now operated at the shallow underground laboratory of the Max-Planck-Institut f\"ur Kernphysik, Heidelberg. Particular attention was paid to the design of a novel passive and active shield, aiming at efficient rejection of environmental and muon induced radiation backgrounds. The achieved sensitivity level of <100 {\mu}Bq/kg for primordial radionuclides from U and Th in typical {\gamma} ray sample screening measurements is unique among instruments located at comparably shallow depths and can compete with instruments at far deeper underground sites.
Production, characterization and operation of $^{76}$Ge enriched BEGe detectors in GERDA
M. Agostini,M. Allardt,E. Andreotti,A. M. Bakalyarov,M. Balata,I. Barabanov,N. Barros,L. Baudis,C. Bauer,N. Becerici-Schmidt,E. Bellotti,S. Belogurov,S. T. Belyaev,G. Benato,A. Bettini,L. Bezrukov,T. Bode,D. Borowicz,V. Brudanin,R. Brugnera,D. Budjas,A. Caldwel,C. Cattadori,A. Chernogorov,V. D'Andrea,E. V. Demidova,A. Domula,V. Egorov,R. Falkenstein,K. Freund,N. Frodyma,A. Gangapshev,A. Garfagnini,C. Gotti,P. Grabmayr,V. Gurentsov,K. Gusev,W. Hampel,A. Hegai,M. Heisel,S. Hemmer,G. Heusser,W. Hofmann,M. Hult,L. V. Inzhechik,L. Ioannucci,J. Janicsko Csathy,J. Jochum,M. Junker,V. Kazalov,T. Kihm,I. V. Kirpichnikov,A. Kirsch,A. Klimenko,K. T. Kn?pfle,O. Kochetov,V. N. Kornoukhov,V. V. Kuzminov,M. Laubenstein,A. Lazzaro,V. I. Lebedev,B. Lehnert,H. Y. Liao,M. Lindner,I. Lippi,A. Lubashevskiy,B. Lubsandorzhiev,G. Lutter,C. Macolino,B. Majorovits,W. Maneschg,M. Misiaszek,I. Nemchenok,S. Nisi,C. O'Shaughnessy,D. Palioselitis,L. Pandola,K. Pelczar,G. Pessina,A. Pullia,S. Riboldi,N. Rumyantseva,C. Sada,M. Salathe,C. Schmitt,J. Schreiner,O. Schulz,B. Schwingenheuer,S. Sch?nert,E. Shevchik,M. Shirchenko,H. Simgen,A. Smolnikov,L. Stanco,H. Strecker,C. A. Ur,L. Vanhoefer,A. A. Vasenko,K. von Sturm,V. Wagner,M. Walter,A. Wegmann,T. Wester,H. Wilsenach,M. Wojcik,E. Yanovich,P. Zavarise,I. Zhitnikov,S. V. Zhukov,D. Zinatulina,K. Zuber,G. Zuzel
Physics , 2014, DOI: 10.1140/epjc/s10052-014-3253-0
Abstract: The GERmanium Detector Array (GERDA) at the Gran Sasso Underground Laboratory (LNGS) searches for the neutrinoless double beta decay (0{\nu}{\beta}{\beta}) of $^{76}$Ge. Germanium detectors made of material with an enriched $^{76}$Ge fraction act simultaneously as sources and detectors for this decay. During Phase I of the experiment mainly refurbished semi-coaxial Ge detectors from former experiments were used. For the upcoming Phase II, 30 new $^{76}$Ge enriched detectors of broad energy germanium (BEGe)-type were produced. A subgroup of these detectors has already been deployed in GERDA during Phase I. The present paper reviews the complete production chain of these BEGe detectors including isotopic enrichment, purification, crystal growth and diode production. The efforts in optimizing the mass yield and in minimizing the exposure of the $^{76}$Ge enriched germanium to cosmic radiation during processing are described. Furthermore, characterization measurements in vacuum cryostats of the first subgroup of seven BEGe detectors and their long-term behavior in liquid argon are discussed. The detector performance fulfills the requirements needed for the physics goals of GERDA Phase~II.
Measurement of the half-life of the two-neutrino double beta decay of Ge-76 with the Gerda experiment
GERDA Collaboration,M. Agostini,M. Allardt,E. Andreotti,A. M. Bakalyarov,M. Balata,I. Barabanov,M. Barnabe Heider,N. Barros,L. Baudis,C. Bauer,N. Becerici-Schmidt,E. Bellotti,S. Belogurov,S. T. Belyaev,G. Benato,A. Bettini,L. Bezrukov,T. Bode,V. Brudanin,R. Brugnera,D. Budjas,A. Caldwell,C. Cattadori,A. Chernogorov,F. Cossavella,E. V. Demidova,A. Denisov,A. Domula,V. Egorov,R. Falkenstein,A. D. Ferella,K. Freund,F. Froborg,N. Frodyma,A. Gangapshev,A. Garfagnini,S. Gazzana,P. Grambayr,V. Gurentsov,K. Gusev,K. K. Guthikonda,W. Hampel,A. Hegai,M. Heisel,S. Hemmer,G. Heusser,W. Hofmann,M. Hult,L. V. Inzhechik,L. Ioannucci,J. Janicsko Csathy,J. Jochum,M. Junker,S. Kianovsky,I. V. Kirpichnikov,A. Kirsch,A. Klimenko,K. T. Knoepfle,O. Kochetov,V. N. Kornoukhov,V. Kusminov,M. Laubenstein,A. Lazzaro,V. I. Lebedev,B. Lehnert,H. Y. Liao,M. Lindner,I. Lippi,X. Liu,A. Lubashevskiy,B. Lubsandorzhiev,G. Lutter,A. A. Machado,B. Majorovits,W. Maneschg,I. Nemchenok,S. Nisi,C. O'Shaughnessy,L. Pandola,K. Pelczar,L. Peraro,A. Pullia,S. Riboldi,F. Ritter,C. Sada,M. Salathe,C. Schmitt,S. Schoenert,J. Schreiner,O. Schulz,B. Schwingenheuer,E. Shevchik,M. Shirchenko,H. Simgen,A. Smolnikov,L. Stanco,H. Strecker,M. Tarka,C. A. Ur,A. A. Vasenko,O. Volynets,K. von Sturm,M. Walter,A. Wegmann,M. Wojcik,E. Yanovich,P. Zavarise,I. Zhitnikov,S. V. Zhukov,D. Zinatulina,K. Zuber,G. Zuzel
Physics , 2012, DOI: 10.1088/0954-3899/40/3/035110
Abstract: The primary goal of the GERmanium Detector Array (Gerda) experiment at the Laboratori Nazionali del Gran Sasso of INFN is the search for the neutrinoless double beta decay of Ge-76. High-purity germanium detectors made from material enriched in Ge-76 are operated directly immersed in liquid argon, allowing for a substantial reduction of the background with respect to predecessor experiments. The first 5.04 kg yr of data collected in Phase I of the experiment have been analyzed to measure the half-life of the neutrino-accompanied double beta decay of Ge-76. The observed spectrum in the energy range between 600 and 1800 keV is dominated by the double beta decay of Ge-76. The half-life extracted from Gerda data is T(1/2) = (1.84 +0.14 -0.10) 10^{21} yr.
The background in the neutrinoless double beta decay experiment GERDA
The GERDA collaboration,M. Agostini,M. Allardt,E. Andreotti,A. M. Bakalyarov,M. Balata,I. Barabanov,M. Barnabe Heider,N. Barros,L. Baudis,C. Bauer,N. Becerici-Schmidt,E. Bellotti,S. Belogurov,S. T. Belyaev,G. Benato,A. Bettini,L. Bezrukov,T. Bode,V. Brudanin,R. Brugnera,D. Budjas,A. Caldwell,C. Cattadori,A. Chernogorov,F. Cossavella,E. V. Demidova,A. Domula,V. Egorov,R. Falkenstein,A. Ferella,K. Freund,N. Frodyma,A. Gangapshev,A. Garfagnini,C. Gotti,P. Grabmayr,V. Gurentsov,K. Gusev,K. K. Guthikonda,W. Hampel,A. Hegai,M. Heisel,S. Hemmer,G. Heusser,W. Hofmann,M. Hult,L. V. Inzhechik,L. Ioannucci,J. Janicsko Csathy,J. Jochum,M. Junker,T. Kihm,I. V. Kirpichnikov,A. Kirsch,A. Klimenko,K. T. Knoepfle,O. Kochetov,V. N. Kornoukhov,V. V. Kuzminov,M. Laubenstein,A. Lazzaro,V. I. Lebedev,B. Lehnert,H. Y. Liao,M. Lindner,I. Lippi,X. Liu,A. Lubashevskiy,B. Lubsandorzhiev,G. Lutter,C. Macolino,A. A. Machado,B. Majorovits,W. Maneschg,I. Nemchenok,S. Nisi,C. O'Shaughnessy,D. Palioselitis,L. Pandola,K. Pelczar,G. Pessina,A. Pullia,S. Riboldi,C. Sada,M. Salathe,C. Schmitt,J. Schreiner,O. Schulz,B. Schwingenheuer,S. Schoenert,E. Shevchik,M. Shirchenko,H. Simgen,A. Smolnikov,L. Stanco,H. Strecker,M. Tarka,C. A. Ur,A. A. Vasenko,O. Volynets,K. von Sturm,V. Wagner,M. Walter,A. Wegmann,T. Wester,M. Wojcik,E. Yanovich,P. Zavarise,I. Zhitnikov,S. V. Zhukov,D. Zinatulina,K. Zuber,G. Zuzel
Physics , 2013, DOI: 10.1140/epjc/s10052-014-2764-z
Abstract: The GERmanium Detector Array (GERDA) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double beta decay of 76Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the Q-value of the decay, Q_bb. To avoid bias in the signal search, the present analysis does not consider all those events, that fall in a 40 keV wide region centered around Q_bb. The main parameters needed for the neutrinoless double beta decay analysis are described. A background model was developed to describe the observed energy spectrum. The model contains several contributions, that are expected on the basis of material screening or that are established by the observation of characteristic structures in the energy spectrum. The model predicts a flat energy spectrum for the blinding window around Q_bb with a background index ranging from 17.6 to 23.8*10^{-3} counts/(keV kg yr). A part of the data not considered before has been used to test if the predictions of the background model are consistent. The observed number of events in this energy region is consistent with the background model. The background at Q-bb is dominated by close sources, mainly due to 42K, 214Bi, 228Th, 60Co and alpha emitting isotopes from the 226Ra decay chain. The individual fractions depend on the assumed locations of the contaminants. It is shown, that after removal of the known gamma peaks, the energy spectrum can be fitted in an energy range of 200 kev around Q_bb with a constant background. This gives a background index consistent with the full model and uncertainties of the same size.
Pulse shape discrimination for GERDA Phase I data
M. Agostini,M. Allardt,E. Andreotti,A. M. Bakalyarov,M. Balata,I. Barabanov,M. Barnabe Heider,N. Barros,L. Baudis,C. Bauer,N. Becerici-Schmidt,E. Bellotti,S. Belogurov,S. T. Belyaev,G. Benato,A. Bettini,L. Bezrukov,T. Bode,V. Brudanin,R. Brugnera,D. Budjá?,A. Caldwell,C. Cattadori,A. Chernogorov,F. Cossavella,E. V. Demidova,A. Domula,V. Egorov,R. Falkenstein,A. Ferella,K. Freund,N. Frodyma,A. Gangapshev,A. Garfagnini,C. Gotti,P. Grabmayr,V. Gurentsov,K. Gusev,K. K. Guthikonda,W. Hampel,A. Hegai,M. Heisel,S. Hemmer,G. Heusser,W. Hofmann,M. Hult,L. V. Inzhechik,L. Ioannucci,J. Janicskó Csáthy,J. Jochum,M. Junker,T. Kihm,I. V. Kirpichnikov,A. Kirsch,A. Klimenko,K. T. Kn?pfle,O. Kochetov,V. N. Kornoukhov,V. V. Kuzminov,M. Laubenstein,A. Lazzaro,V. I. Lebedev,B. Lehnert,H. Y. Liao,M. Lindner,I. Lippi,X. Liu,A. Lubashevskiy,B. Lubsandorzhiev,G. Lutter,C. Macolino,A. A. Machado,B. Majorovits,W. Maneschg,M. Misiaszek,I. Nemchenok,S. Nisi,C. O'Shaughnessy,L. Pandola,K. Pelczar,G. Pessina,A. Pullia,S. Riboldi,N. Rumyantseva,C. Sada,M. Salathe,C. Schmitt,J. Schreiner,O. Schulz,B. Schwingenheuer,S. Sch?nert,E. Shevchik,M. Shirchenko,H. Simgen,A. Smolnikov,L. Stanco,H. Strecker,M. Tarka,C. A. Ur,A. A. Vasenko,O. Volynets,K. von Sturm,V. Wagner,M. Walter,A. Wegmann,T. Wester,M. Wojcik,E. Yanovich,P. Zavarise,I. Zhitnikov,S. V. Zhukov,D. Zinatulina,K. Zuber,G. Zuzel
Physics , 2013, DOI: 10.1140/epjc/s10052-013-2583-7
Abstract: The GERDA experiment located at the LNGS searches for neutrinoless double beta (0\nu\beta\beta) decay of ^{76}Ge using germanium diodes as source and detector. In Phase I of the experiment eight semi-coaxial and five BEGe type detectors have been deployed. The latter type is used in this field of research for the first time. All detectors are made from material with enriched ^{76}Ge fraction. The experimental sensitivity can be improved by analyzing the pulse shape of the detector signals with the aim to reject background events. This paper documents the algorithms developed before the data of Phase I were unblinded. The double escape peak (DEP) and Compton edge events of 2.615 MeV \gamma\ rays from ^{208}Tl decays as well as 2\nu\beta\beta\ decays of ^{76}Ge are used as proxies for 0\nu\beta\beta\ decay. For BEGe detectors the chosen selection is based on a single pulse shape parameter. It accepts 0.92$\pm$0.02 of signal-like events while about 80% of the background events at Q_{\beta\beta}=2039 keV are rejected. For semi-coaxial detectors three analyses are developed. The one based on an artificial neural network is used for the search of 0\nu\beta\beta\ decay. It retains 90% of DEP events and rejects about half of the events around Q_{\beta\beta}. The 2\nu\beta\beta\ events have an efficiency of 0.85\pm0.02 and the one for 0\nu\beta\beta\ decays is estimated to be 0.90^{+0.05}_{-0.09}. A second analysis uses a likelihood approach trained on Compton edge events. The third approach uses two pulse shape parameters. The latter two methods confirm the classification of the neural network since about 90% of the data events rejected by the neural network are also removed by both of them. In general, the selection efficiency extracted from DEP events agrees well with those determined from Compton edge events or from 2\nu\beta\beta\ decays.
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