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[en] Arguments are presented which suggest that the centres of luminescence in CaWO₄ are associated with the intrinsic defects produced by the W⁵⁺ ions. The equilibrium concentration of W⁵⁺ in the luminophor obtained by calcination of CaWO₄ in the air at 1000 deg C has been calculated

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[en] Main types of ionizing radiation detectors applied in medicine are considered. The detectors under consideration are divided into two groups according to their application. The first group consists of detectors designed for measuring values characterizing radiation and its source (dosimetry, spectrometry). The second group contains the means for image visualization. Solid luminescent detectors are widely used in medical dosimetry. Combination of luminescent amplifying screens with a film represents image converter the most widely used in X-Ray radiography

[en] Certain general problems of roentgenological and radionuclide diagnosis were presented. Quality criteria of roentgenological image and its control were given. Quality of scintiscanning images was assessed. Factors defining limiting values of the main specifications of gamma chambers were described. Limiting value of internal spatial resolution was presented. Limiting value of internal spatial resolution of gamma chamber comprised ∼ 0.3 mm in case of scintillation crystal thickness of about 10 mm (by 10 times less in comparison with present day results). Spatial non-linearity (SN) and inhomogeneity of response of gamma-detector was corrected. Accuracy of SN correction was limited by statistics of test measurements and stability of gamma chamber

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No abstract available

[en] The effect of some element impurities on the LaOBr-Tb luminophor optical properties is investigated, the luminophor being used for manufacturing intensifying X-ray screens. It is established that, among lanthanides, Ce³⁺ (luminogen and sensitizer), Sm³⁺ (quencher of stationary luminescence), Eu³⁺ and Yb³⁺ (quenchers of phosphorescense) exert most considerable effect on the LaOBr-Tb luminescence. Such an effect of these ions is explained by the structure of the 4f-shell. The X-ray luminescence amplification of LaOBr-Tb-luminophor is detected following introduction Nb, Dy, Tm, Yb, Fe and Ni into it in concentration approximately 10^-5 g-atom x mol^-1. The effect is explained by suppression of the luminescence quenching conforming to the Auger mechanism. Taces of radioactive impurities accompanying lanthanum are shown to cause weak background radio luminescence due to α-radiation. A high-sensitive photographic-luminescence method for detecting these impurities in the source material (lanthanum oxides) is developed. The significance of the decscribed phenomena for medical and indastrial roentgenography is considered

No abstract available

No abstract available