Papers by Keyword: Radioluminescence

Abstract: Radioluminescence technologies are at the front line of the optic and electronic studies. Effective, self-contained and safe radioluminescent light sources can find their application in space industry, in medicine and in military technologies. The question of the performance improvement of the solid-state radioluminescent light sources (SRLS) without raising the included activity of working radionuclide can be solved by upgrading the phosphor crystalline structure. The electron-beam treatment for zinc-sulphide phosphors initial batch has been studied in a wide range of concentrations of the activating agent (Cu) for improving the radioluminescent performances of the phosphors, for creating the structural defects that form centers of luminescence. The changes of the phase composition were investigated under different synthesis conditions. It is revealed that electron-beam treatment of the initial batch leads to the growth of the wurtzite phase content in zinc-sulphide phosphors synthesized below the phase transition temperature. The changes of the phase content promote the spectral redistribution under the tritium beta-excitation. It is obviously the reflection of the fact of «green» luminescence centers rearrangement between the volume of the crystal and its surface. The correlations between structural configuration and performances of ionizing luminescence were found. Electron beam treatment gave the 20% increase of brightness of the radioluminescence. The achieved enhancement of luminescence performances allows the development of advanced tight-packed SRLS with minimal radioactivity and high energy-light conversion.

Abstract: Photo-and radioluminescence characteristics of Ce³⁺-doped dense oxide glass (SiO₂-B₂O₃-Al₂O₃-Gd₂O₃) are presented. The Gd³⁺→ Ce³⁺ energy transfer was evidenced by photoluminescence excitation spectra of Ce³⁺ emission. Photoluminescence decay kinetics was governed by a few tens of nanoseconds decay time. The integral scintillation efficiency of about 22% of that of the Bi₄Ge₃O₁₂ scintillator was obtained under X-ray irradiation. Scintillation light yield under alpha particle excitation was measured and compared with that of the Bi₄Ge₃O₁₂ crystal.

Abstract: This chapter gives an introduction to instrumentation for stimulated luminescence studies, with special focus on luminescence dating using the natural dosimeters, quartz and feldspars. The chapter covers basic concepts in luminescence detection, and thermal and optical stimulation, and reference irradiation. It then briefly describes development of spectrometers in dating applications, and finally gives an overview of recent development in the field directly linked to novel instrumentation. Contents of Paper

Abstract: A portable fibre optic dosimeter has been developed that uses transparent fluroperovskite dosimeters at the end of a multimode polymer fibre. It uses two stimulation sources that take advantage of the bimodal trap distribution so that the dose rate and cumulative dose can be monitored. Photoluminescence (PL), optically stimulated luminescence (OSL) and radioluminescence (RL) measurements were made on nearly tissue equivalent NaMgF₃:Eu²⁺, NaMgF₃:Mn²⁺, and high sensitivity RbMgF₃:Eu²⁺ and CsCdF₃:Mn²⁺. Initial dose rate and dose measurements were made using our fibre dosimeter during and after exposure to 60 keV gamma rays.

Abstract: Nanocrystalline powders of Lu2O3:Eu with activator content varying between 0.2%-10% were prepared using four different methods of synthesis. The products differed in their microstructure and crystallites sizes. Combustion of Lu(NO3)3 with urea produced strongly agglomerated material, most probably with significantly non-uniform distribution of the Eu3+ dopant. Replacing urea with glycine for the combustion produced only slightly agglomerated, voluminous, fluffy powder. Applying the Pechini technique resulted in significantly agglomerated powder while the homogeneous precipitation of Lu(OH)3 with urea at 90 °C and its subsequent decomposition to Lu2O3 at 650 °C resulted in a powder of perfectly spherical particles with a uniform size of about 130 nm with very low agglomeration. The efficiency of X-ray excited luminescence of our nanocrystalline Lu2O3:5%Eu was compared to that of the commercial microcrystalline Gd2O2S:Eu. It was found that the commercial phosphor performed four times more efficiently than our nanocrystalline powder. We consider this to be rather encouraging as the fabrication of our powder is not optimized yet. It seems that Lu2O3:Eu, even in nanocrystalline form, can perform much more efficiently which would make it a promising X-ray phosphor.