A PbMoO4 single crystal as a perspective detector for neutrinoless double beta decay experiment was grown by the Czochralski technique from high purity raw materials including archaeological lead. ...Charge trapping and energy transfer phenomena in this crystal have been studied by electron paramagnetic resonance (EPR) and wavelength-resolved thermally stimulated luminescence (TSL). EPR revealed several impurities, which however do not participate in the charge trapping processes: Gd3+, Cr3+, Mn2+. Self-trapped electron and (MoO4)3--VPb centers creation under laser light was confirmed. At least six glow peaks related to the thermal release of the charge carriers were observed having maxima at 41 K, 53 K, 83 K, 90 K, 105 K and 118 K. The peak at 41 K was ascribed to the de-trapping of self-trapped electrons. The 53 K one, in particular, is created by re-trapping processes. Partial cleaning procedure followed by the initial rise method allow to determine the trap depths and frequency factors for the 90 K and 105 K glow peaks. They have been referred to the (MoO4)3--VPb decay. A three-component analysis of the spectra could explain the observed 100 nm red shift of the thermo-luminescence emission maximum.
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•PbMoO4 of 6 N purity was synthesized from archaeological lead.•Charge trapping and luminescence peculiarities were investigated.•Participation of accidental impurities in charge trapping was disclosed.
The growing interest in clarifying the controversial situation in the Dark Matter sector has driven the experimental efforts towards new ways to investigate the long-standing DAMA/LIBRA result. Among ...them, low-temperature calorimeters based on Na-containing scintillating crystals offer the possibility to clarify the nature of the measured signal via particle identification. Here we report the first preliminary measurement of Na-containing crystals, based on a material different from NaI, i.e. Na2Mo2O7 and Na2W2O7, pointing out their performance in terms of energy resolution, light yield, and particle identification.
The Gran Sasso National Laboratory in Italy (LNGS) is at present the largest deep underground laboratory in the world. LNGS has been in operation for 35 years. It has a rock overburden of 1.4 km ...which reduces the muon flux from cosmic rays by a factor of one million.
In this article we report on a detailed study of the internal radioactive and chemical contamination of the Li6Eu(BO3)3 scintillating crystal operated as a cryogenic scintillating bolometer over ...359 h. The excellent discrimination power of the detector allows to distinguish effectively beta/gamma events from alpha events. Whilst a weak activity of daughter nuclides from U/Th chains at the level few mBq/kg was observed, this crystal was found to be significantly contaminated by 147Sm, an alpha-active nuclide, at the level of about 0.5 Bq/kg. The light yield for β/γ events was determined to be 7.4(6) keV/MeV. The light yield and quenching factor for alpha particles vary in the range of (0.5–1.2) keV/MeV and (0.07–0.17), respectively, due to energy dependence of the emitted scintillating light in the energy interval (2.0–7.0) MeV. The integral luminescence intensity of the Li6Eu(BO3)3 crystal increases by more than four times only at low temperatures, below 80 K. Therefore, the Li6Eu(BO3)3-based cryogenic scintillating bolometers can be attractive detectors for direct neutron flux monitoring, to search for rare alpha decays or solar axions.
In the field of Double Beta Decay searches the possibility to have high resolution detectors in which a very large part of the natural background can be discriminated with respect to the tiny ...expected signal, results very appealing. This very interesting possibility can be fulfilled in the case of a scintillating crystal bolometer containing a DBD emitter whose transition energy exceeds the one of the natural 2615 keV gamma line of
208
Tl. We present the results achieved in the development of bolometric light detectors for double beta searches. The detectors are 1 mm thick germanium disk coated with a layer of SiO
2
in order to increase the light collection. The adopted temperature sensors are NTD Ge thermistors optimized to work at temperatures between 9 and 13 mK. A light detector with a considerable large area (35 cm
2
) was constructed and run in a test measurement. A 140 g CdWO
4
crystal (
116
Cd has a DBD transition energy of 2802 keV) was operated as bolometer and the scintillation light was read by the light detector. The excellent results combined with extreme easy light detector assembly represent the first tangible proof demonstrating the feasibility of this kind of technique.
An active discrimination of the dominant α-background is the prerequisite for future neutrinoless double-beta decay experiments based on TeO2 bolometers. We investigate such α-particle rejection in ...cryogenic TeO2 bolometers by the detection of Cherenkov light. For a setup consisting of a massive TeO2 crystal (285g) and a separate cryogenic light detector, both using transition edge sensors as temperature sensors operated at around 10mK, we obtain an event-by-event identification of e/γ- and α-events. We find in the energy interval ranging from 2400keV to 2800keV and covering the Q-value of the neutrinoless double-beta decay of 130Te a separation of the means of the two populations of 3.7 times their width.
Abstract
RES-NOVA is a newly proposed experiment for detecting neutrinos from astrophysical sources, mainly Supernovae, using an array of cryogenic detectors made of PbWO
$$_4$$
4
crystals produced ...from archaeological Pb. This unconventional material, characterized by intrinsic high radiopurity, enables low-background levels in the region of interest for the neutrino detection via Coherent Elastic neutrino-Nucleus Scattering (CE
$$\nu $$
ν
NS). This signal lies at the detector energy threshold,
O
(1 keV), and it is expected to be hidden by naturally occurring radioactive contaminants of the crystal absorber. Here, we present the results of a radiopurity assay on a 0.84 kg PbWO
$$_4$$
4
crystal produced from archaeological Pb operated as a cryogenic detector. The crystal internal radioactive contaminations are:
$$^{232}$$
232
Th <40
$$\upmu $$
μ
Bq/kg,
$$^{238}$$
238
U <30
$$\upmu $$
μ
Bq/kg,
$$^{226}$$
226
Ra 1.3 mBq/kg and
$$^{210}$$
210
Pb 22.5 mBq/kg. We also present a background projection for the final experiment and possible mitigation strategies for further background suppression. The achieved results demonstrate the feasibility of realizing this new class of detectors.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The R&D activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first ...large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in Se-82, the (ZnSe)-Se-82 crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three (ZnSe)-Se-82 crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radiopurity complies with the requirements of CUPID-0.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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