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A method for monitoring the degradation of the optical density in films of polytetrafluoroethylene and its modification, a copolymer of tetrafluoroethylene and ethylene, irradiated by electrons with energies of 100 keV and 10 MeV is described. The method is based on measuring the optical density of irradiated films in the photon energy range of 1–6 eV and is confirmed by established “dose–optical absorption” relationships. In particular, using the described method, a completely different nature of the radiation degradation of the optical properties of the two types of films under study was discovered. With an increase in the irradiation dose, “clearing effect” in the region of 2–5 eV and the occurrence of an absorption band at 5.6 eV are observed in polytetrafluoroethylene films. With a similar dose increase, three absorption bands at 4.0, 4.6, and 5.5 eV appear and grow in films of copolymer of tetrafluoroethylene and ethylene. The evidence of the critical role of the optical density of films in the functioning of space technology devices is given. [ABSTRACT FROM AUTHOR]

A prototype of a skin dosimeter with a lower limit of the measured dose range of 100 μSv has been created for an automated system of individual dosimetric control that takes the readings with the use of the effect of optically stimulated luminescence. The energy and dose characteristics of this prototype meet Russian and foreign nuclear safety standards. The obtained results became possible due to the development and implementation of the new approach to the creation of an irradiation-sensitive layer with a mass thickness of 5 mg/cm2 on the detector surface. This is described in this paper. The approach is based on a special laser treatment of the detector surface. The logic of the parameter selection for this treatment is regarded with special attention in this paper. [ABSTRACT FROM AUTHOR]

Lithium–magnesium fluorophosphate with the formula Li9Mg3[PO4]4F3 has recently been proposed as a new thermoluminescent material capable of storing ionizing radiation energy and emitting photons after additional thermal stimulation. Pure and sodium-doped fluorophosphates were obtained by microwave-assisted synthesis. Using X-ray and neutron diffraction methods, it was shown that sodium occupies only one of the three nonequivalent lithium positions. This conclusion was confirmed by a MAS NMR study and ab initio calculations. A significant increase in the thermoluminescence intensity of sodium-containing fluorophosphates in comparison to the undoped compound was found. Analysis of the kinetic parameters obtained from glow curves showed that they are similar for the undoped and sodium-doped samples. This indicates that the addition of sodium does not result in the emergence of novel types of traps, but rather in a change in their number. The effect of sodium on the formation of intrinsic defects, which can be responsible for the enhanced thermoluminescence, is considered using ab initio modelling. [ABSTRACT FROM AUTHOR]

A brief list of the main directions in radiation processes using ionizing radiation in a wide range of doses and energies is given. The necessity of monitoring doses in irradiated objects and diagnosing radiation fields is substantiated. It is noted that in world practice, these problems are solved with the help of dosimetric EPR systems and detectors based on L-α-alanine. Using the example of sterilizing medical devices by radiation from an electron accelerator, a series of experimental results have been obtained that confirm the possibility of using polytetrafluoroethylene as a detector in dosimetric EPR systems for monitoring radiation processes. [ABSTRACT FROM AUTHOR]

The 13C and 19F NMR spectra of the original and irradiated polytetrafluoroethylene samples were studied in the range of gamma radiation doses of up to 50 kGy. In this range, the 19F NMR spectrum width increases linearly with an increase in the absorbed dose. It is concluded that it is possible to monitor technological doses by the NMR method using polytetrafluoroethylene as a detector. [ABSTRACT FROM AUTHOR]

It is established that simple color centers of the F+ and F type (anion vacancies with one or two electrons, respectively) in anion-deficient corundum (α-Al2O3-δ) crystals can be transformed into complex centers (including divacancy centers of the F2 type) using a special thermo-optical treatment. A fine structure of the photoluminescence bands of complex centers of both the known and unknown natures was recorded in these crystals at helium temperatures in the near-IR range. A comparison with the photoluminescence bands in neutron-irradiated α-Al2O3 samples with the initial stoichiometric composition reveals their complete similarity, which indicates the possibility of nonradiative formation of complex centers in α-Al2O3. [ABSTRACT FROM AUTHOR]