[en] The stabilization process of radiation-induced centers such as the non-bridging oxygen atoms in quartz glasses by means of the potential curves in configuration coordinates is considered

[en] The present method is worked out for Sr 90 determination in objects of different origin, especially in agricultural production, cattle production, and food. The method may be applied to determine the Sr 90 contamination of objects and territories, which were exposed to accidents at nuclear energy objects, buffer areas of NPP, and possible use of so called 'dirty' bombs. The principle of the method is based on chromatographic extraction of strontium from nitrate solutions followed by radiometric determination of Sr 90 activity. A highly porous matrix of sty-rene-divinyl benzene in the form of beads ∼1 mm in diameter is used as a substrate to support the extractant, dicy-clohexyl-18-crown-6 (DCH18K6) in tetrachloroethane, which is in the liquid state deep in the pores of the matrix. Dicyclohexyl-18-crown-6 belongs to synthetic macrocyclic polyethers (so-called crown ethers) and has the ability to bind Sr 90 with high selectivity so that Sr 90 is extracted with 90 - 95 % efficiency. To register the equilibrium composition (Sr 90 and Y 90) Vavilov - Cherenkov effect or liquid scintillators are used. The Sr 90 activity is measured with allowance for the scintillating cell background and the conversion factor depending on the Y 90 accumulation time and the Sr 90 and Y 90 detection efficiency. (authors)

[en] The results on studying radiation effects at 4.2 K on paramagnetic centers in glasses are presented. The investigated objects have been irradiated in the cryostat by X rays at 4.2 K. The EPR spectra have been measured at the same temperature. For investigation purposes potassium silicate glasses of the composition 93SiO²x7K²O (mol.%), quartz glasses of the KU-2 type and phosphate glasses of the composition 66P²O⁵x34CaO (mol.%) have been chosen. The forms of lines recorded in EPR spectra testify in favour of such approach when radiation centers in glasses are considered as radicals and not as electron-hole traps. For more detailed decording of mechanism of their formation it is suggested to perform the study in the direction of determining stability ranges of different spectra of radiation paramagnetic centers depending on sample temperature during irradiation as well as on the annealing temperature upon irradiation

No abstract available

[en] Effect of photoradiation of the absorption band of centers F₁ on absorption spectra of lithium and sodium fluoride crystals is investigated. Simultaneous increase of absorption bands together with F₁-band decrease and with maxima about 150 and 380 nm for crystals LiF and NaF correspondingly is detected. On the basis of the results investigating optical and ESR-spectra the given bands can be attributed to centers F₁^-. Photo- and thermostability of centers F₁^- in sodium fluoride crystals are studied

[en] Luminescence of glasses in IR spectrum region after the radiation action is revealed. The correlation between luminescence intensities and EPR signals of Fe³⁺ ions is observed. During the Fe²⁺ ionization its octahedral environment does not change. The Fe²⁺ ion, being formed in this case, is the source of additional bands of radiation and excitation

[en] The mechanism of formation of defects in quartz glasses with the radiactive and thermal action is discussed. The models for photoluminescence centers are suggested and the possibility for modelling radiation processes in quartz glasses by thermal treatment is shown

[en] The radiation-optical characteristics of a number of commercially produced multicomponent optical glasses, subjected to γ-irradiation in the 178--428 K temperature interval, are investigated. Analytical expressions are suggested that make it possible to determine the amount of additional optical absorption of the irradiated glasses as a function of the dosage and the irradiation temperature

[en] Spectra of radiation-induced coloured CaF₂-RE and CaF₂-RE-Na crystal absorption are discussed. Diffeence in spectra of colour centers of CaF₂-RE crystals coloured by fast-neutron flux or gamma radiation appearing when IR absorption band (∼ 945 nm) occurring in the first case is found. Competative character of colour center creation in CaF₂-RE-Na crystals expressed in the possibility of observation of absorbing bands characteristic for both colour centers of CaF₂-RE and for CaF₂-Na colour centers is detected

No abstract available