20 research outputs found
Recent progress in oxide scintillation crystals development by low-thermal gradient Czochralski technique for particle physics experiments
International audienceModern particle physics experiments call for high performance scintillation detectors with unique properties: radiation-resistant in high energy and astrophysics, highly radiopure, containing certain elements or enriched isotopes in astroparticle physics. The low-thermal gradient Czochralski (LTG CZ) crystal growth technique provides excellent quality large volume radiopure crystal scintillators. Absence of thermoelastic stress in the crystal and overheating of the melt in the LTG CZ method is particularly significant in production of crystalline materials with strong thermal anisotropic properties and low mechanical strength, with a very high yield of crystalline boules and low losses of initial charge, crucially important in production of crystal scintillators from enriched isotopes for double beta decay experiments. Here we discuss progress in development of the well known scintillators (Bi(4)Ge(3)O(12) (BGO), CdWO(4), ZnWO(4), CaMoO(4), PbMoO(4)), as well as R{&}D of new materials (ZnMoO(4), Li(2)MoO(4), Na(2)Mo(2)O(7)) for the next generation experiments in particle physics
LiMoO Scintillating Bolometers for Rare-Event Search Experiments
International audienceWe report on the development of scintillating bolometers based on lithium molybdate crystals containing molybdenum depleted in the double- active isotope Mo (LiMoO). We used two LiMoO cubic samples, 45 mm side and 0.28 kg each, produced following purification and crystallization protocols developed for double- search experiments with Mo-enriched LiMoO crystals. Bolometric Ge detectors were utilized to register scintillation photons emitted by the LiMoO crystal scintillators. The measurements were performed in the CROSS cryogenic set-up at the Canfranc underground laboratory (Spain). We observed that the LiMoO scintillating bolometers are characterized by excellent spectrometric performance (3--6 keV FWHM at 0.24--2.6 MeV 's), moderate scintillation signal (0.3--0.6 keV/MeV depending on light collection conditions) and high radiopurity (Th and Ra activities are below a few Bq/kg), comparable to the best reported results of low-temperature detectors based on LiMoO with natural or Mo-enriched molybdenum content. Prospects of LiMoO bolometers for use in rare-event search experiments are briefly discussed
LiMoO Scintillating Bolometers for Rare-Event Search Experiments
International audienceWe report on the development of scintillating bolometers based on lithium molybdate crystals containing molybdenum depleted in the double- active isotope Mo (LiMoO). We used two LiMoO cubic samples, 45 mm side and 0.28 kg each, produced following purification and crystallization protocols developed for double- search experiments with Mo-enriched LiMoO crystals. Bolometric Ge detectors were utilized to register scintillation photons emitted by the LiMoO crystal scintillators. The measurements were performed in the CROSS cryogenic set-up at the Canfranc underground laboratory (Spain). We observed that the LiMoO scintillating bolometers are characterized by excellent spectrometric performance (3--6 keV FWHM at 0.24--2.6 MeV 's), moderate scintillation signal (0.3--0.6 keV/MeV depending on light collection conditions) and high radiopurity (Th and Ra activities are below a few Bq/kg), comparable to the best reported results of low-temperature detectors based on LiMoO with natural or Mo-enriched molybdenum content. Prospects of LiMoO bolometers for use in rare-event search experiments are briefly discussed
The background model of the CUPID-Mo experiment
International audienceCUPID-Mo, located in the Laboratoire Souterrain de Modane (France), was a demonstrator for the next generation decay experiment, CUPID. It consisted of an array of 20 enriched LiMoO bolometers and 20 Ge light detectors and has demonstrated that the technology of scintillating bolometers with particle identification capabilities is mature. Furthermore, CUPID-Mo can inform and validate the background prediction for CUPID. In this paper, we present a detailed model of the CUPID-Mo backgrounds. This model is able to describe well the features of the experimental data and enables studies of the decay and other processes with high precision. We also measure the radio-purity of the LiMoO crystals which are found to be sufficient for the CUPID goals. Finally, we also obtain a background index in the region of interest of 3.7(stat)(syst)counts/E/mol/yr, the lowest in a bolometric decay experiment
Final results on the decay half-life limit of Mo from the CUPID-Mo experiment
The CUPID-Mo experiment to search for 0 decay in Mo has been recently completed after about 1.5 years of operation at Laboratoire Souterrain de Modane (France). It served as a demonstrator for CUPID, a next generation 0 decay experiment. CUPID-Mo was comprised of 20 enriched LiMoO scintillating calorimeters, each with a mass of 0.2 kg, operated at 20 mK. We present here the final analysis with the full exposure of CUPID-Mo (Mo exposure of 1.47 kgyr) used to search for lepton number violation via 0 decay. We report on various analysis improvements since the previous result on a subset of data, reprocessing all data with these new techniques. We observe zero events in the region of interest and set a new limit on the Mo 0 decay half-life of year (stat.+syst.) at 90% C.I. Under the light Majorana neutrino exchange mechanism this corresponds to an effective Majorana neutrino mass of \left < (0.28-- eV, dependent upon the nuclear matrix element utilized