RESUMEN
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.
Asunto(s)
Compuestos de Aluminio/efectos de la radiación , Fluoruro de Calcio/efectos de la radiación , Fluoruros/efectos de la radiación , Compuestos de Litio/efectos de la radiación , Dosimetría Termoluminiscente/métodos , Compuestos de Aluminio/química , Fluoruro de Calcio/química , Cerio/química , Cristalización , Fluoruros/química , Compuestos de Litio/química , Mediciones Luminiscentes , Radioquímica , Espectrofotometría , Espectrofotometría Ultravioleta , Rayos XRESUMEN
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.
Asunto(s)
Tomografía Computarizada de Emisión de Fotón Único/instrumentación , Cámaras gamma , Humanos , Tomografía Computarizada de Emisión de Fotón Único/economíaRESUMEN
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.
RESUMEN
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.