[en] The results of R&D of radiopure zinc molybdate (ZnMoO_4) based scintillating bolometers for the LUMINEU (Luminescent Underground Molybdenum Investigation for NEUtrino mass and nature) double-beta decay experiment are presented. A dedicated two-stage molybdenum purification technique (sublimation in vacuum and recrystallization from aqueous solutions) and an advanced directional solidification method (the low-thermal-gradient Czochralski technique) were utilized to produce high optical quality large mass (∼1 kg) ZnMoO_4 crystal boules and first "1"0"0Mo (99.5%) enriched Zn"1"0"0MoO_4 crystal scintillator (mass of ∼0.2 kg). Scintillating bolometers based on ZnMoO_4 (≈ 0.33 kg) and Zn"1"0"0MoO_4 (≈ 0.06 kg) scintillation elements and high purity Ge wafers were tested in the EDELWEISS set-up at the Modane Underground Laboratory (France). Long term low temperature tests demonstrate excellent detectors’ performance and effectiveness of the purification and solidification procedures for the achievement of high radiopurity of the material, in particular with a bulk activity of "2"2"8Th and "2"2"6Ra below 4 µBq/kg. The adopted protocol was used to produce for the first time a large volume Zn"1"0"0MoO_4 crystal scintillator (mass of ∼1.4 kg, "1"0"0Mo enrichment is 99.5%) to search for neutrinoless double-beta decay of "1"0"0Mo in the framework of the LUMINEU project

[en] We report on the multiple wavelength laser monitoring system designed for the compact muon solenoid (CMS) lead tungstate crystal calorimeter. Results are presented for the test-beam performance of the system designed to achieve ≤0.2% relative optical transmittance inter-calibration for 75 848 lead tungstate crystals. The system cycles continuously over the calorimeter to follow each crystal's evolution under the irradiation and recovery periods foreseen during operation at the LHC

[en] This paper reports on the development of a technology involving ¹⁰⁰Mo-enriched scintillating bolometers, compatible with the goals of CUPID, a proposed next-generation bolometric experiment to search for neutrinoless double-beta decay. Large mass (∝ 1 kg), high optical quality, radiopure ¹⁰⁰Mo-containing zinc and lithium molybdate crystals have been produced and used to develop high performance single detector modules based on 0.2-0.4 kg scintillating bolometers. In particular, the energy resolution of the lithium molybdate detectors near the Q-value of the double-beta transition of ¹⁰⁰Mo (3034 keV) is 4-6 keV FWHM. The rejection of the α-induced dominant background above 2.6 MeV is better than 8σ. Less than 10 μBq/kg activity of ²³²Th(²²⁸Th) and ²²⁶Ra in the crystals is ensured by boule recrystallization. The potential of ¹⁰⁰Mo-enriched scintillating bolometers to perform high sensitivity double-beta decay searches has been demonstrated with only 10 kg x d exposure: the two neutrino double-beta decay half-life of ¹⁰⁰Mo has been measured with the up-to-date highest accuracy as T_1/2 = [6.90 ± 0.15(stat.) ± 0.37(syst.)] x 10¹⁸ years. Both crystallization and detector technologies favor lithium molybdate, which has been selected for the ongoing construction of the CUPID-0/Mo demonstrator, containing several kg of ¹⁰⁰Mo. (orig.)