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A search for neutrinoless ... decay processes accompanied with Majoron emission has been performed using data collected during Phase I of the GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Processes with spectral indices ... were searched for. No signals were found and lower limits of the order of 10... yr on their half-lives were derived, yielding substantially improved results compared to previous experiments with ...Ge. A new result for the half-life of the neutrino-accompanied ... decay of ...Ge with significantly reduced uncertainties is also given, resulting in ... yr.

(ProQuest: Abstract omitted; see image)[PUBLICATION ABSTRACT]

The detectors are made from germanium with the fraction of the 76Ge isotope enriched from 7.8% to about 87%. Since the source and the detector of Ovßß decay are identical in this calorimetric approach, the detection efficiency is high. A rock overburden of about 3,500 m water equivalent removes the hadronic components of cosmic ray showers and reduces the muon flux at the experiment by six orders of magnitude, to 1.2 muons m-2 h-1.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The GERmanium Detector Array (Gerda) at the Gran Sasso Underground Laboratory (LNGS) searches for the neutrinoless double beta decay (...) of ...Ge. Germanium detectors made of material with an enriched ...Ge fraction act simultaneously as sources and detectors for this decay. During Phase I of theexperiment mainly refurbished semi-coaxial Ge detectors from former experiments were used. For the upcoming Phase II, 30 new ...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 ...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.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) The GERmanium Detector Array (Gerda) at the Gran Sasso Underground Laboratory (LNGS) searches for the neutrinoless double beta decay (...) of ...Ge. Germanium detectors made of material with an enriched ...Ge fraction act simultaneously as sources and detectors for this decay. During Phase I of theexperiment mainly refurbished semi-coaxial Ge detectors from former experiments were used. For the upcoming Phase II, 30 new ...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 ...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.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) The GERmanium Detector Array (Gerda) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double beta (...) decay of ...Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the ... value of the decay. 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 ... The main parameters needed for the ... 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 ... with a background index ranging from 17.6 to 23.8 ... ... cts/(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 ... is dominated by close sources, mainly due to ...K, ...Bi, ...Th, ...Co and ... emitting isotopes from the ...Ra decay chain. The individual fractions depend on the assumed locations of the contaminants. It is shown, that after removal of the known ... peaks, the energy spectrum can be fitted in an energy range of 200 keV around ... with a constant background. This gives a background index consistent with the full model and uncertainties of the same size.

The Gerda collaboration is performing a search for neutrinoless double beta decay of ^sup 76^Ge with the eponymous detector. The experiment has been installed and commissioned at the Laboratori Nazionali del Gran Sasso and has started operation in November 2011. The design, construction and first operational results are described, along with detailed information from the R&D phase.

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.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The GERmanium Detector Array (Gerda) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double beta (...) decay of ...Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the ... value of the decay. 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 ... The main parameters needed for the ... 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 ... with a background index ranging from 17.6 to 23.8 ... ... cts/(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 ... is dominated by close sources, mainly due to ...K, ...Bi, ...Th, ...Co and ... emitting isotopes from the ...Ra decay chain. The individual fractions depend on the assumed locations of the contaminants. It is shown, that after removal of the known ... peaks, the energy spectrum can be fitted in an energy range of 200 keV around ... with a constant background. This gives a background index consistent with the full model and uncertainties of the same size.

The Gerda collaboration is performing a search for neutrinoless double beta decay of super(76)Ge with the eponymous detector. The experiment has been installed and commissioned at the Laboratori Nazionali del Gran Sasso and has started operation in November 2011. The design, construction and first operational results are described, along with detailed information from the R&D phase.