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A search for resonant absorption of solar axions by 169 Tm nuclei was carried out. A newly developed approach involving low-background cryogenic bolometer based on Tm 3 Al 5 O 12 crystal was used that allowed for significant improvement of sensitivity in comparison with previous 169 Tm based experiments. The measurements performed with 8.18 g crystal during 6.6 days exposure yielded the following limits on axion couplings: | g A γ ( g AN 0 + g AN 3 ) ≤ 1.44 × 10 - 14 GeV - 1 and | g Ae ( g AN 0 + g AN 3 ) ≤ 2.81 × 10 - 16 .

The composition, structure and mechanical properties of Ti–Al–Ta–N coatings obtained by high-power impulse magnetron sputtering and direct current magnetron sputtering have been studied using energy-dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, and nanoindentation. It has been established that for high-power impulse sputtering, the current and power of the magnetron discharge increase exponentially during the pulse and reach peak values that are an order of magnitude higher than similar characteristics for magnetron sputtering at direct current. A high level of ionization of the sputtered particles caused a significant increase in the number of ions in the particle flux deposited on the substrate. The suppression of the growth of columnar grains and the formation of a denser and more homogeneous microstructure were ensured by an increase in the intensity of ion bombardment of the growing coating. This made it possible to improve its mechanical characteristics.

X-ray spectra of natural germanium sample irradiated in the fast neutron flux were measured using Si(Li)-detector during 4800 hours. The half-life of the Ge nucleus was evaluated to be days that is consistent with the recent results whilst having a higher accuracy. The possibility of explaining the ‘‘gallium anomaly’’ due to a longer lifetime of Ge nucleus is therefore strictly rejected.

The search for neutrino events in correlation with gravitational wave (GW) events for three observing runs (O1, O2 and O3) from 09/2015 to 03/2020 has been performed using the Borexino data-set of the same period. We have searched for signals of neutrino-electron scattering and inverse beta-decay (IBD) within a time window of [Formula omitted] s centered at the detection moment of a particular GW event. The search was done with three visible energy thresholds of 0.25, 0.8 and 3.0 MeV. Two types of incoming neutrino spectra were considered: the mono-energetic line and the supernova-like spectrum. GW candidates originated by merging binaries of black holes (BHBH), neutron stars (NSNS) and neutron star and black hole (NSBH) were analyzed separately. Additionally, the subset of most intensive BHBH mergers at closer distances and with larger radiative mass than the rest was considered. In total, follow-ups of 74 out of 93 gravitational waves reported in the GWTC-3 catalog were analyzed and no statistically significant excess over the background was observed. As a result, the strongest upper limits on GW-associated neutrino and antineutrino fluences for all flavors ( [Formula omitted]) at the level [Formula omitted] have been obtained in the 0.5-5 MeV neutrino energy range.

A search for resonant absorption of solar axions by [Formula omitted] nuclei was carried out. A newly developed approach involving low-background cryogenic bolometer based on [Formula omitted] crystal was used that allowed for significant improvement of sensitivity in comparison with previous [Formula omitted] based experiments. The measurements performed with 8.18 g crystal during 6.6 days exposure yielded the following limits on axion couplings: [Formula omitted] and [Formula omitted].

A search for axioelectric absorption of solar axions produced in the reactions has been performed with a BGO detector placed in a low-background setup. A model-independent limit on an axion-nucleon and axion–electron coupling constant has been obtained: for 90 % confidence level. The constrains of the axion–electron coupling have been obtained for hadronic axion with masses in (0.1–1) MeV range: | g Ae |≤(1.4–9.7)×10 −7 .

Photoelectric properties of MIS tunnel diodes produced on high-resistive p-type silicon wafers with thin aluminium nitride AlN insulator layer and Pd or Al metal gate electrodes were investigated. It was found that synthesized AlN films possess a fixed positive charge, which leads to the creation of near-surface inversion layer in silicon substrate. The ratio of the photocurrent to the dark current K = Iph / Idark (on / off ratio) was found to depend on the gate electrode material, illumination intensity and the applied reverse bias. For studied MIS structures K ratio varied from 10 4 to 10 5 and was two orders of magnitude higher than that for the control MS structure without the insulator layer. High on / off ratio of such MIS structures with AlN tunnelling insulator promotes their application as an effective photodetectors in optoelectronics.

Deterioration of the operation parameters of p-type Si surface-barrier detector and Si(Li) p-i-n detector upon irradiation by alpha-particles was investigated. The detectors were irradiated at room temperature up to a total number of the registered α-particles N α equal to 6 × 10 9 . Prolonged irradiation has resulted in a deterioration of the detectors energy resolution ability and it was found that the increase of α-peaks broadening can be described by a linear function of N α with a slope Δσ/Δ N α ∼ (1.4–1.8) × 10 –9 keV/α for both detectors. Resolution deterioration was associated with the increase of the detectors leakage current, which proceeds linearly with the number of absorbed α-particles with the slope ΔI/Δ Nα ∼ (7-17) × 10 -17 A/α. The increase of the detectors reverse current was related with appearance of radiation-induced defect level at 0.56 eV above the valence band.

Present work reports the results of activities intended to reach thin Si(Li) detector entrance window on the diffusive lithium layer side. It was established that the new n-contact represented by a heterostructure of unalloyed amorphous n-type silicon a-Si:H allows one to achieve the entrance window thickness 3 - 4 orders of magnitude smaller than the lithium-side entrance window of standard Si(Li) detectors. The films of amorphous silicon were synthesized with MASD (magnetron assisted silane decomposition) method in mixture of SiH4 (25%) and Ar (75%) gases. Lithium layer surface resistivity and silicon target type (n- or p-) affection on electrical properties of Si(Li) detector contact produced were studied. The investigation performed had led to a technology of Si(Li) detector production with thickness of the entrance window on the diffusive lithium layer side below 0.1 µm.