S. Kaewjaeng

Luminescence characteristics of Dy3+ doped Gd2O3-CaO-SiO2-B2O3 scintillating glasses

Abstract Glasses were prepared from the compositions of 25Gd 2 O 3 -10CaO-10SiO 2 -(55– x )B 2 O 3 - x Dy 2 O 3 (where x is 0.0 mol.%–1.0 mol.%) by the conventional melt-quenching technique at 1400 °C. The results demonstrated the increase in the glass density with respect to the increase in the doping concentrations of Dy 2 O 3 . Nine absorption bands were observed. The emission spectra of the developed glass showed two strong peaks at 577 nm ( 4 F 9/2 → 6 H 13/2 ) and 482 nm ( 4 F 9/2 → 6 H 15/2 ). The highest emission intensity was observed from the developed glass prepared at 0.4 mol.% of Dy 2 O 3 , as the efficient energy transfer took place from Gd 3+ to Dy 3+ . From the X-ray induced optical luminescence, the emission spectra were identical to those from PL measurements, but with the highest intensity observed from the glass quenched at 0.45 mol.% of Dy 2 O 3 . Finally, the integral scintillation efficiency of the developed glass was determined at 27% of that of the commercially available BGO crystal.

Bone mineral density at distal forearm in men over 40 years of age in Mae Chaem district, Chiang Mai Province, Thailand: a pilot study

Abstract Objective: To study the prevalence of bone mineral density (BMD) and osteoporosis in the distal forearm among Thai men over 40 years of age in Mae Chaem District, Chiang Mai Province, Thailand. Methods: The subjects in this study were 194 Thai men, aged between 40 and 87 years who resided in Mae Chaem District, Chiang Mai Province, Thailand. Self-administered questionnaires were used for receiving the demographic characteristics information. BMD was measured by peripheral dual energy X-ray absorptiometry at the nondominant distal forearm in all men. Results: The BMD was highest in the age-group 40–49 years and lowest in the age-group 70–87 years. The average T-score at the distal forearm was also highest in the age-group 40–49 years and lowest in the age-group 70–87 years. The BMD decreased as a function of age-group (p < .05). In contrast, the BMD increased as a function of weight (p < .05). Height had weak impact on the BMD in the distal forearm (p > .05). The percentage of osteopenia and osteoporosis are increased as a function of age-group in, while decreased in that of normal bone density. Conclusions: We found the prevalence of osteoporosis in men who resided in Mae Chaem District, Chiang Mai Province, Thailand.

Radiation Shielding Properties of BaO-ZnO-B2O3 Glass for X-Ray Room

This study is to find a parameters that necessary for fabricating a radiation shielding glass in x-ray room. In this study, we performed a comparison of commercial lead glass product commercial window, and developed lead-free glass in the composition of xBaO:20ZnO:(80-x)B2O3 which are applied used for lead glass replacement. The result found that, the linear attenuation coefficients (m) were increased with the increase of BaO concentrations and the decrease of an x-ray tube voltage. The developed glass samples were investigated in terms of half value layer (HVL) and mean free path (MFP) that found to be decreased with the increase of BaO concentrations which the good characteristics for application in a x-ray shielding glass manufacturing.

Optical and Luminescence Properties of Pr3+ in Gd2O3-CaO-SiO2-B2O3 Glasses

This paper reports on the results concerning optical absorption and luminescence properties of 25Gd2O3-10CaO-10SiO2-(55-x) B2O3-xPr2O3 (where x is 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol %) have been synthesized by melting and quenching process. The locations of the absorption peak observed are investigated for the first time. It is shown that the f-f transitions in the studied glasses are allowed by distortions of Pr3+ ions. Seven absorption bands corresponding to the 3H4 → 3P2, 1I6+3P1, 1D2, 1G4, 3F4, 3F3 and 3F2, respectively absorption bands peaked at 459,483,575,1011,1418,1513 and 1931 nm. The luminescence intensity of Pr3+ doped glass under excited at 459 and 483 nm, the emission band under excited at 459 nm wavelengths emission centered at 542 nm (3P0→3H5), 602 nm (1D2→3H4), 646 nm (3P0→3F2) and 689 nm (1D2→3H5) .The emission bands with 483 nm excitation wavelength, the emission band centered at 532 nm (3P1→3H5), 602 nm (1D2→3H4), 646 nm (3P0→3F2) and 725 nm (3P0→3F4), respectively. The present paper brings out the results pertaining to the studies carried out on different structural and optical absorption in UV-VIS-NIR region are also measured and discussed in term of energy levels, energy band gap and emission spectra of Pr3+ ions doped in Gd2O3-CaO-SiO2-B2O3 glasses.

Mass Attenuation Coefficients and Partial Interactions of BaO-ZnO-B2O3 Glasses System

The mass attenuation coefficients and partial interactions of BaO-ZnO-B2O3 glasses have been investigated using WinXCom program at difference photon energy. BaO-ZnO-B2O3 glasses were prepared in composition xBaO: 20ZnO: (80-x)B2O3 (where x = 15 and 20 mol %) by melt quenching technique under normal atmosphere. The densities of glasses are 3.0052 and 3.1022 g/cm3, respectively. The mass attenuation coefficients at 20% mol are higher than 15% mol of BaO in all energy range. The optical spectra were measured and good transparent behavior was obtained. Half value layer (HVL) of glasses are also report and compared with same standard shielding materials and show better shielding than ordinary concrete.

Upconversion Luminescence Study of Er3+ in Gadolinium-Calcium- Silicoborate Glasses

The new glass series were prepared in compositions 25Gd2O3-10CaO-10SiO2-(55-x) B2O3-xEr2O3 (where x is 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol %) by normal melt-quenching technique at the melting temperature of 1,400 °C. The optical spectra were measured and shown absorption bands were assigned to appropriate f-f electronic transitions of Er3+ ions from the 4I15/2 ground state to the following excited states: 4G11/2, 2H9/2, 4F5/2, 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I9/2 and 4I11/2. Single peak from upconversion luminescence was observed at 531 nm (green) is assigned to the 2H11/24I15/2. In this work, the strongest peak at 2.0 % mol of Er2O3 was observed. In this work, suggests that the Er3+ ion in gadolinium calcium silicoborate glasses possibly considered as a potential candidate for applications in upconversion-based optical devices.