Search for tri-nucleon decays of 76Ge in GERDA Agostini, M.; Alexander, A.; Bakalyarov, A. M. ...
The European physical journal. C, Particles and fields,
09/2023, Letnik:
83, Številka:
9
Journal Article
Recenzirano
Odprti dostop
We search for tri-nucleon decays of
76
Ge in the dataset from the GERmanium Detector Array (GERDA) experiment. Decays that populate excited levels of the daughter nucleus above the threshold for ...particle emission lead to disintegration and are not considered. The ppp-, ppn-, and pnn-decays lead to
73
Cu,
73
Zn, and
73
Ga nuclei, respectively. These nuclei are unstable and eventually proceed by the beta decay of
73
Ga to
73
Ge (stable). We search for the
73
Ga decay exploiting the fact that it dominantly populates the 66.7 keV
73
m
Ga state with half-life of 0.5 s. The nnn-decays of
76
Ge that proceed via
73
m
Ge are also included in our analysis. We find no signal candidate and place a limit on the sum of the decay widths of the inclusive tri-nucleon decays that corresponds to a lower lifetime limit of 1.2
×
10
26
yr (90% credible interval). This result improves previous limits for tri-nucleon decays by one to three orders of magnitude.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Trigger performance verification of the FlashCam prototype camera Sailer, S.; Werner, F.; Hermann, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
Odprti dostop
FlashCam is a camera proposed for the medium-sized telescopes of the Cherenkov Telescope Array (CTA). We compare camera trigger rates obtained from measurements with the camera prototype in the ...laboratory and Monte Carlo simulations, when scanning the parameter space of the fully-digital trigger logic and the intensity of a continuous light source mimicking the night sky background (NSB) during on-site operation. The comparisons of the measured data results to the Monte Carlo simulations are used to verify the FlashCam trigger logic and the expected trigger performance.
We search for tri-nucleon decays of
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Ge in the dataset from the GERmanium Detector Array (GERDA) experiment. Decays that populate excited levels of the daughter nucleus above the threshold for particle emission lead to disintegration and are not considered. The ppp-, ppn-, and pnn-decays lead to
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Cu,
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Zn, and
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Ga nuclei, respectively. These nuclei are unstable and eventually proceed by the beta decay of
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73
Ga to
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Ge (stable). We search for the
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Ga decay exploiting the fact that it dominantly populates the 66.7 keV
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73
m
Ga state with half-life of 0.5 s. The nnn-decays of
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76
Ge that proceed via
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73
m
Ge are also included in our analysis. We find no signal candidate and place a limit on the sum of the decay widths of the inclusive tri-nucleon decays that corresponds to a lower lifetime limit of 1.2
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×
10
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26
yr (90% credible interval). This result improves previous limits for tri-nucleon decays by one to three orders of magnitude.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
An optimized digital shaping filter has been developed for the
Gerda
experiment which searches for neutrinoless double beta decay in
76
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
Q
value for
0
ν
β
β
decay in
76
Ge is obtained. This is possible thanks to the enhanced low-frequency noise rejection of this Zero Area Cusp (ZAC) signal shaping filter.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron ...capture of Formula omittedAr has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array (Gerda) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of Formula omittedAr was established: Formula omitted 3.6 Formula omitted 10 Formula omitted years at 90% CI.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Neutrinoless double-
β
decay of
76
Ge is searched for with germanium detectors where source and detector of the decay are identical. For the success of future experiments it is important to increase ...the mass of the detectors. We report here on the characterization and testing of five prototype detectors manufactured in inverted coaxial (IC) geometry from material enriched to 88% in
76
Ge. IC detectors combine the large mass of the traditional semi-coaxial Ge detectors with the superior resolution and pulse shape discrimination power of point contact detectors which exhibited so far much lower mass. Their performance has been found to be satisfactory both when operated in vacuum cryostat and bare in liquid argon within the
Gerda
setup. The measured resolutions at the
Q
-value for double-
β
decay of
76
Ge (
Q
β
β
= 2039 keV) are about 2.1 keV full width at half maximum in vacuum cryostat. After 18 months of operation within the ultra-low background environment of the GERmanium Detector Array (
Gerda
) experiment and an accumulated exposure of 8.5 kg
·
year, the background index after analysis cuts is measured to be
4
.
9
-
3.4
+
7.3
×
10
-
4
counts
/
(
keV
·
kg
·
year
)
around
Q
β
β
. This work confirms the feasibility of IC detectors for the next-generation experiment
Legend
.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We present the first search for bosonic superweakly interacting massive particles (super-WIMPs) as keV-scale dark matter candidates performed with the GERDA experiment. GERDA is a neutrinoless ...doubleβ decay experiment which operates high-purity germanium detectors enriched in 76 Ge in an ultralow background environment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for pseudoscalar and vector particles in the mass region from 60 keV / c 2 to 1 MeV / c 2 . No evidence for a dark matter signal was observed, and the most stringent constraints on the couplings of super-WIMPs with masses above 120 keV / c 2 have been set. As an example, at a mass of 150 keV / c 2 the most stringent direct limits on the dimensionless couplings of axionlike particles and dark photons to electrons of g a e < 3 × 10 − 12 and α ′ / α < 6.5 × 10 − 24 at 90% credible interval, respectively, were obtained.
Neutrinoless double-
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β
decay of
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76
Ge is searched for with germanium detectors where source and detector of the decay are identical. For the success of future experiments it is important to increase the mass of the detectors. We report here on the characterization and testing of five prototype detectors manufactured in inverted coaxial (IC) geometry from material enriched to 88% in
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76
Ge. IC detectors combine the large mass of the traditional semi-coaxial Ge detectors with the superior resolution and pulse shape discrimination power of point contact detectors which exhibited so far much lower mass. Their performance has been found to be satisfactory both when operated in vacuum cryostat and bare in liquid argon within the
Gerda
setup. The measured resolutions at the
Q
-value for double-
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β
decay of
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76
Ge (
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Q
β
β
= 2039 keV) are about 2.1 keV full width at half maximum in vacuum cryostat. After 18 months of operation within the ultra-low background environment of the GERmanium Detector Array (
Gerda
) experiment and an accumulated exposure of 8.5 kg
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·
year, the background index after analysis cuts is measured to be
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\begin{document}$$4.9^{+7.3}_{-3.4}\times 10^{-4} \ \text {counts}/(\text {keV} \cdot \text {kg} \cdot \text {year})$$\end{document}
4
.
9
-
3.4
+
7.3
×
10
-
4
counts
/
(
keV
·
kg
·
year
)
around
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Q
β
β
. This work confirms the feasibility of IC detectors for the next-generation experiment
Legend
.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The GERmanium Detector Array (
Gerda
) is a low background experiment located at the Laboratori Nazionali del Gran Sasso in Italy, which searches for neutrinoless double-beta decay of
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76
Ge into
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76
Se+2e
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-
.
Gerda
has been conceived in two phases. Phase II, which started in December 2015, features several novelties including 30 new
76
Ge enriched detectors. These were manufactured according to the Broad Energy Germanium (BEGe) detector design that has a better background discrimination capability and energy resolution compared to formerly widely-used types. Prior to their installation, the new BEGe detectors were mounted in vacuum cryostats and characterized in detail in the
Hades
underground laboratory in Belgium. This paper describes the properties and the overall performance of these detectors during operation in vacuum. The characterization campaign provided not only direct input for
Gerda
Phase II data collection and analyses, but also allowed to study detector phenomena, detector correlations as well as to test the accuracy of pulse shape simulation codes.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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