Vol 46, No 7 (2019)

Among classical applications of superconductivity, superconductor bolometers representing a superconducting thin-film strip in the resistive state occupy an important place [1-4]. The present study concerns HTSC bolometer samples based on YBa₂Cu₃O_7−δ with a PrBa₂Cu₃O_x protective layer. For the first time, the thermal resistance at the YBa₂Cu₃O_7−δ-PrBa₂Cu₃O_x epitaxial interface is quantitatively estimated from the response to pulses of a Ti:Al₂O₃ laser as (0.3 ÷ 1.3) · 10⁻³ K·cm²/W.

Dose distributions of 6-MeV electrons in the region of edges of metal and plastic collimators are compared using calculated and experimental data. The results of the study show an insignificant disagreement in the dose distributions: the difference in the penumbra widths does not exceed 1.1 mm.

One of the key problems in the ICF program is the development of rapid methods for forming cryogenic fuel targets (CFT) for their feeding to the focus of a high-power laser setup or an ICF reactor. The simulation results on temporal parameters of the formation of reactor-scaled CFTs by the free-standing target (FST) method are presented. The CFT design includes hollow 4-mm-diameter shells of compact and porous polymers, containing solid hydrogen fuel on the inner surface. It is shown that the time of the cryogenic layer formation in the targets does not exceed 30 s, which makes it possible to implement line production of reactor-scaled CFTs based on the FST method.

Polycrystalline zinc selenide is doped with an iron impurity to a concentration of ~10¹⁹ cm⁻³ in a zinc vapor atmosphere by the thermal diffusion method, and the distribution profile of optically active iron Fe²⁺ is obtained. The effect of the Fe²⁺ concentration on impurity-and defect-related ZnSe luminescence spectra at low temperatures is determined. In the range of 1.28—1.31 eV, a luminescence line with a decay time of ~0.341 ms is detected, with its intensity increasing in regions with Fe²⁺ concentration close to the maximum one. The line is attributed to the luminescence center arising due to the Fe²⁺ interaction with a background impurity or defect in ZnSe.