الفهرس 
BORATE GLASSESOnly 14 pages are availabe for public view
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Abstract
There is always a need for high efficient, less expensive, tissue equivalent, high stability, and low dose measurement radiation detectors in markets for general uses in the field of radiation dosimetry. For this purpose, newly oxyfluroborate glass system of structures (80-x)B2O3–10Al2O3–10SiO2- xCaF2 (or shortly, BASC system) was prepared where x=5, 10, 15, 20, 25, 30, 35 and 40 mole %. The conventional melt-quenching method was used in preparation. The glass samples was checked using X-ray diffraction (XRD) pattern and showed the amorphous state of all prepared samples. Fourier Transform Infrared (FTIR) spectroscopic technique was used and showed that BASC system of lower CaF2 content has open structure than higher one. UV-visible absorption spectra were also measured in wavelength range 190-2500 nm where the optical absorption spectra from UV study of BASC glass systems showed that, the absorption edge is shifted towards the lowest wavelength direction as CaF2 content increases. The optical energy gap (Eopt), for indirect allowed transitions showed a decrease with increasing the CaF2 content with energy-band gap in the range (2.91 eV - 3.41 eV). Differential Scanning Calorimetry (DSC) was carried out and indicated that BASC10 (70B2O3–10Al2O3–10SiO2-10CaF2) showed the highest thermal stability between the others.
Gamma-mass absorption coefficients of glass systems were calculated using the WinXCom software. Compton scattering probability was found to be the predominant effect among the others. Dosimetrical properties of -irradiated glass samples were investigated, in detail, using thermoluminescent (TL) technique before and after doping with some activators. BASC10 glass sample showed the best TL properties among all other glass samples. Four different concentrations of Er, Pr, Ag and Cu activators and were introduced in BASC10 system. Peaks under TL glow curves were deconvoluted using GlowFit software. The dosimetric characteristics of 250 ppm Cu-BASC10 glass samples showed a high dosimetric efficiency where excellent linearity responses were obtained and accurately checked using the linearity index approximation method. Two ranges of -doses were studied, one was from 0.3 to 300 mGy and the other was from 0.4 to 12.38 Gy. In addition the 250 ppm Cu-BASC10 system showed a good linearity index and low detectable limit of 0.27 mGy. The reproducibility of the prepared glass was studied for some chips from each type separately and compared with the International Electrotechnical Commission (IEC) requirements. Also, the 250 ppm Cu-BASC10 is proved to be a reasonably acceptable -detector in comparison with the commercials TLD-100 and TLD-600 detectors. Thermal fading study of the glow curves showed there two groups of traps ranged (700C -2000C) and (2000C-4000C). The second groups showed low fading up to about 135 d.