Подготовлено кафедрой экспериментальной физики ФТИ при поддержке Центра интеллектуальной собственности и Института инноватики и маркетинга УрФУ.

The neutron induced defects in activated LiF and NaF single crystals have been investigated by studying the absorption and luminescence spectra. For LiF and NaF neutron irradiated crystals the creation of F, F-2 and F-3(+) aggregate color centers have been analysed in comparison with F, F-2 and F-3(+)-center production in NaF crystals irradiated by ion and electron beams. (c) 2007 WILEYNCH Verlag GmbH & Co. KGaA, Weinheim.

In this work experimental data on electron fluxes with energies of 30-500 keV obtained from the ACTIVE satellite experiment (INTERCOSMOS-24 in 1989-1990, altitude from 500 km up to 2500 km) and ones with energies 0.3-1.0 MeV obtained onboard the MIR station (SPRUT-VI experiment in 1999, altitude from 350 km up to 400 km) are presented. The distribution of electron fluxes at low and middle latitudes and the influence of charged particles on surface layers of materials and film coverings are investigated. The comparison with results of other satellite experiments reveals the time and spatial stability of electron flux enhancements at L = 1.2-1.8.

1 The work was supported by Detector Technology Center LTD (Ekaterinburg, Russia), FIBERCRYST firm (France), "University of Russia" grant (UR.02.01.433), NATO grant NoPST.EAP.CLG 980674, ISTC grant NoKR-994 and RussianAmerican program "Fundamental research and high education" (fond CRDF REC-005: grant ЕК-005-Х1 Ural scienceeducated center "Advantage materials" Abstract – Some new original results on advanced scintillation materials and detection systems for registration gamma-rays, neutrons, neutrinos, beta-particles, electron and ion radiation are presented.

An analysis of the influence of low energy charged particles onto the surface charging doses of spacecraft was conducted using data from ACTIVE (InterCosmos 24) satellite, SPRUT-VI experiment on board MIR station and the SAMPEX satellite. The surface doses were calculated in the materials up to 10–20 μm in depth. The obtained results were compared against the AE 8 model and a conclusion was reached that the contribution of “abnormal” (i.e., unaccounted in the models electron peaks at L < 2) electron fluxes in the surface dose is insignificant at altitudes less than 600 km.

The photoluminescence (PL), PL excitation, and PL decay kinetics of 6 Li 2 O-MgO-SiO 2 -Ce glasses were studied using time-resolved VUV spectroscopy. The Ce 3+ ion PL excitation spectrum contains a known group of structural bands at 4.4–5.2 eV caused by 4 f → 5 d transitions. Moreover, features at 6.4–7.7 eV were detected and their nature is discussed. At an exciting photon energy E exc > 25 eV, the photon multiplication effect manifests itself. Based on 6 Li-silica glasses, a scintillation neutron detector with improved parameters was developed and produced.

The time-resolved emission spectra (2–6eV), reflection and luminescence excitation spectra (4.5–35eV) as well as the kinetics of luminescence have been studied for single crystals of silicates A2SiO5–Ce (A=Y, Gd, Lu) and Sc2SiO5 at 5.8 and 300K using synchrotron radiation of X-ray (storage ring VEPP-3) or selective vacuum ultraviolet (storage ring DORIS) range. The spectral and decay parameters of the impurity and intrinsic luminescence are determined. The photon multiplication effect was found for all compounds for energy E>15eV (E>2.5Eg). The role of electron-hole and exciton mechanisms of energy transfer in the silicates and their dependence on temperature are discussed.

Electronic excitations and the processes of their radiative relaxation are studied in pure and Ce3+ ion-doped crystals of lanthanum beryllate excited by synchrotron radiation in the x-ray and VUV ranges by methods of optical and luminescent vacuum ultraviolet time-resolved spectroscopy. Manifestations of excitons of the valence band are absent in the reflection spectra. However, a fast (τ=1.7 ns) and a slow (microsecond range) channel corresponding to two possible types of self-trapped excitons (STE) are found in radiative relaxation of intrinsic electronic excitations at T=10 K. The slow channel corresponds to emission of STE formed through recombination, the fast channel corresponds to emission of relaxed metastable excitons from the STE state. In the energy region higher than 14 eV (E>2Eg), the effect of multiplication of electronic excitations due to generation of secondary electron-hole pairs resulting from inelastic scattering of both hot photoelectrons and hot photoholes is exhibited.

CaF{sub 2}-Eu crystals belong to the group of scintillating materials which are promising for recording x-rays and for selective dosimetry and spectrometry of beta radiation on the background of gamma radiation or neutrons. Since they are prepared in the form of thin sheets with h less than 4-5 mm, these crystals are not very sensitive to background radiation. The efficiency of recording beta radiation remains high, particularly since the losses due to backscattering are slight as a consequence of the low effective atomic number. This article discusses the design of the scintillation detectors, measurement techniques and instruments employed, and results of measurements made with detectors equipped with CaF{sub 2}-Eu that included findings regarding the optimal admixture concentration to ensure the highest yield, absolute energy yield, spectrum of the principal emission, temperature effects on luminescence, attenuation curves, temperature dependence of the light yield, etc.

Reflection, luminescence excitation and thermoluminescence excitation spectra have been measured for Bi4Ge3O12 and Bi4Si3O12 crystals in the energy range from 3 to 35 eV using synchrotron radiation. The reflection data are evaluated using a modified Kramers-Kronig method for extracting the information on optical constants of these crystals. The nature of electronic excitations in the fundamental absorption edge region is discussed, the value of forbidden-gap energy Eg is estimated as 5.0 eV for Bi4Ge3O12 and 5.4 eV for Bi4Si3O12. Intrinsic luminescence with 2.5 eV maximum for Bi4Si3O12 and 2.45 eV maximum for Bi4Ge3O12 is due to both the relaxation of optically created excitons and recombination processes. The multiplication effect of electron excitations in E ⩾ 2 Eg for these crystals is due to the inelastic scattering of hot photoelectrons and hot photoholes.