Effect of structural changes on luminescent and dosimetric properties of nanoscale aluminum oxide.

Variations of the particle size and porosity of the alumina ceramics synthesized by annealing compacted nanopowder at 1500-1700°С in vacuum for various periods of time have been studied by SEM. Particle size distributions, which depend on the conditions of the ceramics synthesis, were obtained and discussed. The formation of fine grains and the growth of their fraction with the increasing annealing temperature increase the thermoluminescence intensity and expands the usable dose range upwards.

Dosimetric response for crystalline and nanostructured aluminium oxide to a high-current pulse electron beam.

The main thermoluminescent (TL) and dosimetric properties of the detectors based on anion-defective crystalline and nanostructured aluminium oxide after exposure to a high-current pulse electron beam are studied. TL peaks associated with deep-trapping centres are registered. It is shown that the use of deep-trap TL at 200-600°С allows registering absorbed doses up to 750 kGy for single-crystalline detectors and those up to 6 kGy for nanostructured ones.

Mechanism of quantum dot luminescence excitation within implanted SiO2:Si:C films.

Results of the investigation of photoluminescence (PL) mechanisms for silicon dioxide films implanted with ions of silicon (100 keV; 7 × 10(16) cm(-2)) and carbon (50 keV; 7 × 10(15)-1.5 × 10(17) cm(-2)) are presented. The spectral, kinetic and thermal activation properties of the quantum dots (Si, C and SiC) formed by a subsequent annealing were studied by means of time-resolved luminescence spectroscopy under selective synchrotron radiation excitation.

Deep-trap competition model for TL in alpha-Al2O3:C heating stage.

The present report deals with the experimental observations of the thermally stimulated migration of charge carriers from trapping centres responsible for the main thermoluminescence (TL) peak at 450 K to a deep trap and, also, the optically stimulated transport of carriers from the deep trap to the main trap, which gives rise to the phototransferred TL at 450 K, in anion-defective alpha-Al2O3 crystals. The obtained results provide an experimental proof to the adequacy of the assumptions made in the model of the mutual interaction of the main and deep traps in the crystals under study.

Transformation of the excitation energy in aniondefective corundum.

Some regular features of the excitation energy transformation in anion-defective crystals of alpha-Al2O3 were analysed by the sub-nanosecond spectroscopic method. The samples were excited using synchrotron radiation and high-density pulsed electron beams. It was shown that much of the energy of the ionising radiation absorbed by the crystals was liberated as the luminescence of F- and F-centres immediately at the moment of irradiation.