arXiv subjects

A. A. Klimenko

Publications and source records attributed to A. A. Klimenko.

12 recordsLinked to original sources

arXiv2025

Fabrication of thin planar radiopure foils with 82Se for the SuperNEMO Demonstrator

The SuperNEMO Demonstrator, designed to search for double beta decay using enriched 82Se, has been assembled in the Modane Underground Laboratory under the French Alps. Thin foils with radio - purified and enriched 82Se are installed centrally in the detector. A novel foil fabrication method has been developed, improving the radiopurity achieved in the previous generation experiment. It consists of wrapping standalone selenium pads in raw Mylar, combined with selenium purified by a new reverse-chromatography method. This paper describes the features of these foils, their fabrication process, the characterization results, and the integration of the foils into the SuperNEMO Demonstrator.

physics.ins-det↗

arXiv2025

Calorimeter commissioning of the SuperNEMO Demonstrator

The SuperNEMO experiment is searching for neutrinoless double beta decay of \textsuperscript{82}Se, with the unique combination of a tracking detector and a segmented calorimeter. This feature allows to detect the two electrons emitted in the decay and measure their individual energy and angular distribution. The SuperNEMO calorimeter consists of 712 plastic scintillator blocks readout by large PMTs. After the construction of the demonstrator calorimeter underground, we have performed its first commissioning using $γ$-particles from calibration sources or from the ambient radioactive background. This article presents the quality assurance tests of the SuperNEMO demonstrator calorimeter and its first time and energy calibrations, with the associated methods.

physics.ins-det↗

arXiv2020

Improved limits on $β^+$EC and ECEC processes in $^{74}$Se

New limits on $β^+$EC and ECEC processes in $^{74}$Se have been obtained using a 600 cm$^3$ HPGe detector and an external source consisting of 1600 g of a natural selenium powder. For different $β^+$EC and ECEC transitions (to the ground and excited states) obtained limits are on the level $\sim (0.2-4.8)\times10^{19}$ yr at 90\% C.L. In particular, for the potentially resonant transition into the 1204.2 keV excited state of $^{74}$Ge a lower half-life limit of $1.1\times10^{19}$ yr at 90\% C.L. has been obtained. Possibility to increase the sensitivity of such measurements is discussed.

nucl-ex↗

arXiv2003

Pulse Shape Discrimination in the IGEX Experiment

The IGEX experiment has been operating enriched germanium detectors in the Canfranc Underground Laboratory (Spain) in a search for the neutrinoless double decay of 76Ge. The implementation of Pulse Shape Discrimination techniques to reduce the radioactive background is described in detail. This analysis has been applied to a fraction of the IGEX data, leading to a rejection of ~60 % of their background, in the region of interest (from 2 to 2.5 MeV), down to ~0.09 c/(keV kg y).

hep-ex↗

arXiv2002

Status of IGEX dark matter search at Canfranc Underground Laboratory

One IGEX 76Ge double-beta decay detector is currently operating in the Canfranc Underground Laboratory in a search for dark matter WIMPs, through the Ge nuclear recoil produced by the WIMP elastic scattering. In this talk we report on the on-going efforts to understand and eventually reject the background at low energy. These efforts have led to the improvement of the neutron shielding and to partial reduction of the background, but still the remaining events are not totally identified. A tritium contamination or muon-induced neutrons are considered as possible sources, simulations and experimental test being still under progress. According to the success of this study we comment the prospects of the experiment as well as those of its future extension, the GEDEON dark matter experiment.

astro-ph↗

arXiv2002

The Igex 76ge Neutrinoless Double-Beta Decay Experiment: Prospects for Next Generation Experiments

The International Germanium Experiment (IGEX) has analyzed 117 mole yr of 76Ge data from its isotopically enriched (86% 76Ge) germanium detectors. Applying pulse-shape discrimination (PSD) to the more recent data, the lower bound on the half-life for neutrinoless double-beta decay of 76Ge is: $T_{1/2}(0ν)> 1.57 \times 10^{25}$ yr (90% C.L.). This corresponds to an upper bound in the Majorana neutrino mass parameter,$ $, between 0.33 eV and 1.35 eV, depending on the choice of theoretical nuclear matrix elements used in the analysis.

hep-ex↗

arXiv2002

Improved constraints on WIMPs from the International Germanium Experiment IGEX

One IGEX 76Ge double-beta decay detector is currently operating in the Canfranc Underground Laboratory in a search for dark matter WIMPs, through the Ge nuclear recoil produced by the WIMP elastic scattering. A new exclusion plot, has been derived for WIMP-nucleon spin-independent interactions. To obtain this result, 40 days of data from the IGEX detector (energy threshold E \~ 4 keV), recently collected, have been analyzed. These data improve the exclusion limits derived from all the other ionization germanium detectors in the mass region from 20 GeV to 200 GeV, where a WIMP supposedly responsible for the annual modulation effect reported by the DAMA experiment would be located. The new IGEX exclusion contour enters, by the first time, the DAMA region by using only raw data, with no background discrimination, and excludes its upper left part. It is also shown that with a moderate improvement of the detector performances, the DAMA region could be fully explored.

hep-ex↗

arXiv2001

Present status of IGEX dark matter search at Canfranc Underground Laboratory

One IGEX 76Ge double-beta decay detector is currently operating in the Canfranc Underground Laboratory in a search for dark matter WIMPs, through the Ge nuclear recoil produced by the WIMP elastic scattering. A new exclusion plot has been derived for WIMP-nucleon spin-independent interactions. To obtain this result, 40 days of data from the IGEX detector (energy threshold 4 keV), recently collected, have been analyzed. These data improve the exclusion limits derived from all the other ionization germanium detectors in the mass region from 20 GeV to 200 GeV, where a WIMP supposedly responsible for the annual modulation effect reported by the DAMA experiment would be located. The new IGEX exclusion contour enters, by the first time, the DAMA region by using only raw data, with no background discrimination, and excludes its upper left part. It is also shown that with a moderate improvement of the detector performances, the DAMA region could be fully explored.

hep-ex↗

arXiv2001

Search for Nuclear Reactions in Water Molecules

A possibility for molecular-nuclear transitions to occur was recently predicted for some few-atomic systems. Among others, the molecule of ordinary water was shown to be a candidate for this effect due to a presence of (1-, 4.522 MeV) resonance in 18Ne nucleus. A search for traces of nuclear reactions was carried out for condenced and vaporous phases of water, with the use of low-background annihilation spectrometry. The measurements were performed under conventional conditions and under conditions of the Baksan Neutrino Observatory.

nucl-ex↗

arXiv2000

New constraints on WIMPs from the Canfranc IGEX dark matter search

The IGEX Collaboration enriched 76Ge double-beta decay detectors are currently operating in the Canfranc Underground Laboratory with an overburden of 2450 m.w.e. A recent upgrade has made it possible to use them in a search for WIMPs. A new exclusion plot has been derived for WIMP-nucleon spin-independent interaction. To obtain this result, 30 days of data from one IGEX detector, which has an energy threshold of ~4 keV, have been considered. These data improve the exclusion limits derived from other germanium diode experiments in the ~50 GeV DAMA region, and show that with a moderate improvement of the background below 10 keV, the DAMA region may be tested with an additional 1 kg-year of exposure.

hep-ex↗

arXiv2000

Experimental search for molecular-nuclear transitions in water

Experimental search for molecular-nuclear transitions H_2O\to^{18}Ne^*(4.522,1^-)\to^{18}F\to^{18}O in water molecules was carried out. The measurements were performed in a low-background laboratory at the Baksan Neutrino Observatory. Under the assumption that the above transitions take place, the estimate for the half-life time of water molecule was found to be about 10^{18} years.

nucl-ex↗

arXiv2000

The preliminary results of fast neutron flux measurements in the DULB laboratory at Baksan

One of the main sources of a background in underground physics experiments (such as the investigation of solar neutrino flux, neutrino oscillations, neutrinoless double beta decay, and the search for annual and daily Cold Dark Matter particle flux modulation) are fast neutrons originating from the surrounding rocks. The measurements of fast neutron flux in the new DULB Laboratory situated at a depth of 4900 m w.e. in the Baksan Neutrino Observatory have been performed. The relative neutron shielding properties of several commonly available natural materials were investigated too. The preliminary results obtained with a high-sensitive fast neutron spectrometer at the level of sensitivity of about 10^(-7) neutron/ (cm^2 sec) are presented and discussed.

physics.ins-det↗