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Free keywords:
Physics, Instrumentation and Detectors, physics.ins-det,High Energy Physics - Experiment, hep-ex,Nuclear Experiment, nucl-ex
MPINP:
GERDA - Abteilung Hofmann
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.
