[en] The functioning of mononuclear in white non-linear rats under action acute ionizing irradiation in 1 and 10 Gy doses is studied. Experimental animals were immunisated tissue 3-component-antigens (thymus, medulla, lien). Effects were observed during 1, 10, 30, 90 days. It was found that supplementary antigen-loading at first activated mononuclear, but afterwards depressed them. (authors)

[en] The results of the ²⁰⁹Bi NQR experiments carried out on α-Bi₂O₃, Bi₃O₄Br, Bi₂M₄O₉ (M=Al, Ga), Bi₂Ge₃O₉, and Bi₄Ge₃O₁₂ showed that these compounds are not diamagnets in the conventional sense. The Zeeman perturbed zero-field ²⁰⁹Bi NQR spectra gave an indication that local ordered magnetic fields of the order of 30-200 G exist in these substances comprising neither transition nor rare earth elements. Further aspects of this principally new phenomenon of yet unknown nature were studied by the ²⁰⁹Bi NQR experiments on the Bi₄Ge₃O₁₂ single crystal in external magnetic fields below 500 Oe, applied at various orientations with respect to the crystal axes. The spectral patterns of dramatically increased intensity and multiplicity, caused by the unknown magnetism of the compound, were observed in applied fields and modeled. Based on the results of the modeling, the conclusions were made that at least four magnetically non-equivalent Bi sites characterized by antiferromagnetically ordered local fields of the order of 30 G are present in the Bi₄Ge₃O₁₂ crystal; the intensity increase was interpreted to arise from the change in orientation of the electric field gradient axes at the Bi site upon applying an external magnetic field

[en] The work is devoted to the measurement of optical parameters of aerogel which can be used as Cherenkov light radiator. The refractive index, the light scattering and absorption lengths, the variation of the refractive index inside an aerogel block were measured for the aerogel produced conjointly by the Institute of Catalysis and Institute of Nuclear Physics (Novosibirsk). Atomic and nuclear properties of the aerogel are presented

[en] The possibility of aerogel tiles production for RICH detectors is described. Monolithic blocks of silica aerogel were synthesized by two-step sol-gel processing of tetraethoxysilane Si(OEt)₄ followed by high temperature supercritical drying with organic solvent. The important characteristic of aerogel is the light scattering length. In the wide range of refraction indexes the light scattering length exceeds 4 cm at 400 nm

[en] It is desirable that the detector for an asymmetrical B Factory should provide charged particle identification in the momentum range up to ∼6 GeV/c. We suggest how this might be accomplished either by using a combination of a simple RICH counter and a threshold gas Cherenkov counter with a Csl + TMAE photocathode, or by using two such threshold gas Cherenkov counters with different thresholds

[en] Synthesis of silica aerogel for Cherenkov counters is being studied for more than 10 years at the Boreskov Institute of Catalysis in collaboration with the Budker Institute of Nuclear Physics. Index of refraction, light scattering length and light absorption length are optical characteristics which determine the quality of aerogel Cherenkov counter. These parameters were measured for the aerogel produced. The results are presented

[en] The structure of the alkali-metal hexaiodozirconates(IV) and hexaiodohafnates(IV) is distinguished by its great diversity. The high-symmetry phases with regular [MI₆]^2- anion octahedrons are present, however, in different temperature ranges for all the compounds except the potassium salts. Phase transitions of the first and second kinds were discovered in the hexaiodometalates of sodium and rubidium. In the case of the sodium salts, the high-temperature phases have a lower symmetry than do the low-temperature phases, and the phase transitions are characterized by extensive hysteresis regions

[en] In this work we present a newly developed TDC (Time-to-Digital Converter) board in the VME-32 standard. The 32-channel TDC board is based on a single FPGA Altera Cyclone III chip. The main parameters of the TDC are as follows: a resolution of 1.19 ns, a dead time of 4.76 ns, and a maximal time interval of 19 504 ns.

[en] In this research, we evaluated the timing resolution of SiPM-based scintillation detector on a 1-GeV electron beam "extracted" from VEPP-4M. We tested small scintillation crystals of pure CsI, YAP, LYSO, and LFS-3 with HAMAMATSU S10362-33-025C and S13360-3050CS. The CsI scintillator together with HAMAMATSU S13360-3050CS demonstrated the best results. Nevertheless, the achieved time resolution of ∼80 ps (RMS) relates mainly to the photodetector itself. It makes the silicon photomultiplier an attractive candidate to replace other devices in applications where sub-nanosecond accuracy is required.

[en] We registered axial profiles of electron temperature, plasma potential and concentration of the direct current glow discharge in nitrogen at different gas pressure and discharge current values. We observed that in a broad range of experimental conditions the plasma concentration experiences 15 - 16 times decrease along the negative glow length. Maximum values of plasma concentration and electron temperature are registered at the cathode end of the negative glow, and the electric field strength is small. On leaving the cathode the plasma concentration and electron temperature in the negative glow are decreasing, here a region with a negative field may also form.