[en] The data collected with a radioactively pure ZnWO₄ crystal scintillator (699 g) in low background measurements during 2130 h at the underground (3600 m w.e.) Laboratori Nazionali del Gran Sasso (INFN, Italy) were used to set a limit on possible concentration of superheavy eka-W (seaborgium Sg, Z = 106) in the crystal. Assuming that one of the daughters in a chain of decays of the initial Sg nucleus decays with emission of high energy α particle ($Q_{\mathrm{\alpha <!--\; ??\; -->}}><!--\; >\; -->8$ MeV) and analyzing the high energy part of the measured α spectrum, the limit N(Sg)/N(W) $<<!--\; <\; -->5.5\times <!--\; ??\; -->{10}^{-<!--\; ???\; -->14}$ atoms/atom at 90% C.L. was obtained (for Sg half-life of 10⁹ yr). In addition, a limit on the concentration of eka-Bi was set by analysing the data collected with a large BGO scintillation bolometer in an experiment performed by another group (Cardani et al 2012 JINST 7 P10022): N(eka-Bi)/N(Bi) $<<!--\; <\; -->1.1\times <!--\; ??\; -->{10}^{-<!--\; ???\; -->13}$ atoms/atom with 90% C.L. Both the limits are comparable with those obtained in recent experiments which instead look for spontaneous fission of superheavy elements or use the accelerator mass spectrometry. (paper)

[en] The LUMTNEU program aims at performing a pilot experiment on 0ν2β decay of "1"0"0Mo using radiopure ZnMoO_4 crystals enriched in "1"0"0Mo operated as cryogenic scintillating bolometers. Large volume ZnMoO_4 crystal scintillators (∼ 0.3 kg) were developed and tested showing high performance in terms of radiopurity, energy resolution and α/β particle discrimination capability. Zinc molybdate crystal scintillators enriched in "1"0"0Mo were grown for the first time by the low-thermal-gradient Czochralski technique with a high crystal yield and an acceptable level of enriched molybdenum irrecoverable losses. A background level of ∼ 0.5 counts/(yr keV ton) in the region of interest can be reached in a large detector array thanks to the excellent detectors radiopurity and particle discrimination capability, suppression of randomly coinciding events by pulse-shape analysis, and anticoincidence cut. These results pave the way to future sensitive searches based on the LUMTNEU technology, capable of approachingand exploring the inverted hierarchy region of the neutrino mass pattern

[en] In June-August 2006 an expedition with the aim to look for low-radioactive archaeological lead at the bottom of the Black Sea, near the Crimean peninsula (Ukraine) was organised by a Korean-Ukrainian collaboration. The first samples with ∼0.2 tons of total mass were found at a depth of 28 m among the relics of an ancient Greek ship. Their age has been dated to the first century B.C. This lead was used as ballast in the keel of the ship. The element composition of the samples was measured by means of X-ray fluorescence and ICP-MS analyses. The first preliminary limits on the 210Pb contamination of the samples are less than a few hundreds mBq/kg. The measurements were performed using gamma spectroscopy with HPGe-detectors and alpha spectroscopy with commercial α-detectors. Measurements of 40K, Th/U in the lead samples were undertaken in Kiev and in the underground laboratories of the Laboratori Nazionali del Gran Sasso (LNGS, Italy). If it was found to be radio-clean this lead could be used as high efficiency shield for ultra low-level detectors, and as raw material for growing radio-pure scintillation crystals such as PbMoO4 or PbWO4 for the search for rare processes

[en] An experiment to measure the 2β ^– decay of ¹⁵⁰Nd to excited levels of ¹⁵⁰Sm using a highly purified 2.381 kg sample of Nd₂O₃ is in progress in the low-background set-up with 4 HPGe detectors (∼225 cm³ volume each). The detector is located deep underground (3600 m w.e.) at the STELLA facility of the Gran Sasso National Laboratory (LNGS) of the INFN (Italy). Two γ quanta with energies 334.0 keV and 406.5 keV emitted after deexcitation of the 0₁ ⁺ excited level of ¹⁵⁰Sm have been observed in the experimental data accumulated over 39898 h. The preliminary half-life value for 2β ^– decay of ¹⁵⁰Nd to the first 0⁺ excited level in ¹⁵⁰Sm (after the exposure of 10.8 kg × yr) was estimated as $T_{1/2}=[{9.7}_{-<!--\; ???\; -->1.9}^{+2.9}\left(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}.\right)\pm <!--\; ??\; -->1.5\left(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}.\right)]\times <!--\; ??\; -->{10}^{19}$ yr. The experiment is under data taking with the aim to improve the statistical uncertainties. (paper)

[en] Double beta processes in ⁶⁴Zn, ⁷⁰Zn, ¹⁸⁰W, and ¹⁸⁶W have been searched for with the help of low background ZnWO4 crystal scintillators at the Gran Sasso National Laboratories of the INFN (Italy). The total measurement time exceeds ten thousand hours. New improved half-life (T_1/2) limits on double electron capture and electron capture with positron emission in ⁶⁴Zn have been set. New T_1/2 bounds were also set on different modes of 2β processes in ⁷⁰Zn, ¹⁸⁰W, and ¹⁸⁶W. Future perspectives are considered.

[en] A search for double beta decay of ^64,70Zn, ^180,186W was carried out by using low background ZnWO₄ crystal scintillators, while a CeCl₃ scintillation detector was applied to investigate 2β processes in ^136,138,142Ce. A search for 2β decay of ^96,104Ru, ^156,158Dy, ^190,198Pt and study of 2ν2β decay of ¹⁰⁰Mo to the first excited 0⁺ level of ¹⁰⁰Ru were realized by ultra-low background HPGe γ spectrometry. Moreover, CdWO₄ crystal scintillators from enriched ¹⁰⁶Cd and ¹¹⁶Cd isotopes were developed to search for 2β decay of ¹⁰⁶Cd and ¹¹⁶Cd. Finally, experiments aimed to investigate ^96,104Ru and ¹¹⁶Cd are in progress and a new phase of the experiment to search for 2β processes in ¹⁰⁶Cd is in preparation.

[en] The Aurora experiment to investigate double beta decay of ¹¹⁶ Cd with the help of 1.162 kg cadmium tungstate crystal scintillators enriched in ¹¹⁶ Cd to 82% is in progress at the Gran Sasso Underground Laboratory. The half-life of ¹¹⁶ Cd relatively to the two neutrino double beta decay is measured with the highest up-to-date accuracy T_1/2 = (2.62 ± 0.14) × 10¹⁹ yr. The sensitivity of the experiment to the neutrinoless double beta decay of ¹¹⁶ Cd to the ground state of ¹¹⁶ Sn is estimated as T_1/2 ≥ 1.9 × 10²³ yr at 90% CL, which corresponds to the effective Majorana neutrino mass limit (mv) ≤ (1.2 — 1.8) eV. New limits are obtained for the double beta decay of ¹¹⁶ Cd to the excited levels of ¹¹⁶ Sn, and for the neutrinoless double beta decay with emission of majorons. (paper)

[en] Sample of ¹⁰⁰MoO₃ with molybdenum enriched in ¹⁰⁰Mo to 99.5% and mass of 1199 g was measured deep underground (3600 m w.e.) in the Laboratori Nazionali del Gran Sasso of INFN, Italy; during 17249 h with a low-background set-up with 4 HP Ge detectors. After 2β2ν decay of ¹⁰⁰Mo to the 0⁺₁ excited level of ¹⁰⁰Ru (E_exc = 1131 keV), two γ quanta of 540 keV and 591 keV should be emitted in deexcitation process. Both these γ's are observed in the accumulated data as in coincidence spectrum as well in 1-dimensional sum spectrum. Measured half life is T_1/2 (7.0^+1.1_-0.8) x 10²⁰ yr, in agreement with positive results obtained in previous experiments.

[en] β decay of ¹¹³Cd was studied with the help of a low background CdWO₄ crystal scintillator (mass of 434 g) in an experiment at the Gran Sasso National Laboratories of the INFN for a period of 2758 h. The shape of the spectrum of the non-unique fourth-forbidden decay of ¹¹³Cd was measured, and the half-life of ¹¹³Cd was determined as T_1/2=(8.04±0.05)x10¹⁵ yr

[en] Double-beta processes in ¹⁸⁴Os and ¹⁹²Os were searched for over 15 851 h at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N. by using a 118 g ultra-pure osmium sample installed on the endcap of a 112 cm³ ultra-low-background broad-energy germanium detector. New limits on double-electron capture and electron capture with positron emission in ¹⁸⁴Os were set at the level of lim T _1/2 ∼ 10¹⁶–10¹⁷ years. In particular the 2ν2K and 2ν KL decays of ¹⁸⁴Os to the ground state of ¹⁸⁴W are restricted as T _1/2 ⩾ 3.0 × 10¹⁶ years and T _1/2 ⩾ 2.0 × 10¹⁶ years, respectively. A lower limit on the half-life for the double-beta decay of ¹⁹²Os to the first excited level of ¹⁹²Pt was set as lim T _1/2 = 2.0 × 10²⁰ years at 90% confidence level (paper)