M.A. Terekhin

CROSS LUMINESCENCE OF SEVERAL PEROVSKITE-TYPE CRYSTALS

Cross‐luminescence excitation and decay of crystals RbCaF3, CsCaCl3, and CsSrCl3 have been studied in the vacuum ultraviolet region. It has been shown that decay curves are not single exponential. The effect of structural phase transition on the cross‐luminescence decay time of RbCaF3 has been discovered.

Station for VUV-spectroscopy at beam line M of the storage ring Siberia-I

Abstract The station for solid state VUV-spectroscopy on the dedicated SR source Siberia-I of the Kurchatov Institute, USSR, is described. The station consists of a beam line, vacuum normal-incidence primary Wadsworth monochromator, sample chamber, secondary monochromator and a computer control system. Characteristics of the optical scheme are discussed. The experimental procedure in the VUV range is described.

Temperature dependence of cross-luminescence bandwidth

Abstract The temperature dependence of bandwidths in cross-luminescence spectra of alkali-halide crystals (CsBr, CsCl, CsF, RbF) is analysed on the basis of the model of local optical centre in the vibrating lattice environment. The temperature behaviour of some emission bands can be reasonably well described by the model, the frequency of phonons responsible for the temperature-dependent broadening being close to characteristic frequencies of the host lattice vibrations.

Fast crystalline scintillators for high counting rate X-ray detectors

Abstract Luminescent properties of BaF 2 , BaY 2 F 8 , KMgF 3 and CeF 3 single crystals were studied using the pulsed excitation by the synchrotron radiation from SRS (Daresbury Laboratory). The observed luminescence decay kinetics is discussed in terms of the excitation energy transfer either to the surface centres (in the VUV energy range where the absorption coefficient is high) or to the correlated excitations (in the region where the energy of the absorbed photon is sufficient for the creation of several electronic excitations) with the subsequent nonradiative decay.

Luminescence excitation in BaF2‐BaCl2 and BaF2‐BaBr2 synchrotron radiation

Luminescence excitation spectra in barium fluorohalides have been studied using synchrotron radiation of the SIBERIA‐I electron storage ring in the energy range from 4 to 35 eV. The energy position of edge and core exciton formation as well as that of the electronic excitation multiplication threshold have been established. These luminophors find their practical application in the novel image‐plate technique.

Time-resolved studies of emission properties of cerium-doped fluoro-hafnate glasses under VUV synchrotron radiation excitation

Abstract The emission and excitation spectra as well as the decay kinetics of cerium-doped fluoro-hafnate glasses of various compositions have been studied using vacuum ultraviolet synchrotron radiation excitation. It has been found that iso-valent modifications of the glass composition do not strongly affect the decay kinetics of cerium emission while two-valent oxygen ions create additional quenching centres leading to a decrease of the light yield. It has been shown that the quenching of Ce emission in cerium-doped fluoro-hafnate glasses starts with a process of impact excitation of cerium emission centres. The results show that the dominant mechanism of energy transfer from the matrix to cerium emission centres in fluoride glasses is different for the 315 nm band and the 400 nm band.

Luminescence excitation of barium fluorohalides by using synchrotron radiation

Abstract Luminescence excitation spectra of barium fluorohalides are studied using synchrotron radiation of the Siberia-1 electron storage ring in the energy range from 4 to 35 eV. The energy position of edge and core excitation formation as well as that of the electronic excitation multiplication threshold have been established.

Excitation of stationary and photostimulated luminescence of BaFBr: Eu-phosphors in the range 4 to 25 eV

Abstract Stationary (spontaneous) and photostimulated luminescence excitation spectra of BaFBr:Eu-phosphors have been measured using synchrotron radiation. It is shown that Eu-concentration and low-temperature annealing (550±100°C) have a strong effect on these spectra.

A station for VUV spectroscopy with the Seya-Namioka monochromator at the Siberia-1 storage ring

Abstract The station for solid-state VUV spectroscopy on the dedicated SR source Siberia-1 of the Kurchatov Institute, USSR, is described. The station consists of a beam line, a Seya-Namioka monochromator with toroidal focusing mirrors, a high-vacuum sample chamber and a computer control system. Characteristics of the optical scheme are discussed.

Crossluminescence for detection of structural phase transition in RbCaF3

Crossluminescence excitation and decay for fluorperovskite RbCaF3 has been studied in the VUV region. It has been shown that decay curves were not single exponential. The effect of structural phase transition on the crossluminescence decay time of RbCaF3 has been discovered.