ABSTRACT
Studies on the crystal structure and luminescence properties have been performed for the NaPr(1-x)Ce(x)P(4)O(12) polyphosphate series. Excitation and emission spectra of Pr(3+) and Ce(3+) luminescence from NaPrP(4)O(12):Ce(3+) clearly reveal an efficient Pr(3+ ) â Ce(3+) energy transfer via migration over the Pr(3+)-sub-lattice and a nonradiative resonant transfer to the Ce(3+) ions. Analysis on scintillation characteristics of the NaPr(1-x)Ce(x)P(4)O(12) series shows a maximum light yield of 11,000 ± 1000 ph MeV(-1) for NaPr(0.99)Ce(0.01)P(4)O(12), proving the studied polyphosphates to be promising for application in the detection of x-ray and gamma quanta.
ABSTRACT
LiYP(4)O(12) polyphosphate doped with Ce(3+) ions was prepared by the melt solution technique. The crystal structure, interatomic distances, and atom coordination numbers were determined using x-ray powder diffraction. A study of the spectral-kinetic luminescent properties was performed employing excitation with pulsed radiation from a synchrotron (UV-VUV range) and a laboratory x-ray source. The characteristics of Ce(3+) luminescence, namely the emission doublet maxima at 3.97 and 3.72 eV and the 4f-5d excitation maxima at 4.20, 5.11, 5.40, 5.65 and 6.55 eV, are discussed in terms of crystal field splitting in a low-symmetry site of the LiYP(4)O(12) host lattice. The location of the Ce(3+) energy levels with respect to the valence and conduction bands of the LiYP(4)O(12) host is estimated from the temperature dependence of the decay time measured for Ce(3+) 5d-4f luminescence.
ABSTRACT
The "OFEKT-1" emission tomograph, worked out on the basis of gamma camera, is described. The results of technical and medical testing of the tomograph are presented.
Subject(s)
Tomography, Emission-Computed, Single-Photon/instrumentation , Gamma Cameras , Humans , Tomography, Emission-Computed, Single-Photon/economicsABSTRACT
Absorption, emission and thermostimulated luminescence (TSL) of as-grown and X ray irradiated pure and Ce-doped LiCaAlF6 crystals were investigated. Ce-containing samples demonstrate intensive TSL in the UV region (280-310 nm) with a main peak at 350 degrees C. It is found that the well known UV laser crystal LiCaAlF6:Ce is a promising thermoluminescent dosemetric material.
