Gopi Sharma

Optical and structural properties of ZnO–PbO–B2O3 and ZnO–PbO–B2O3–SiO2 glasses

Borate and borosilicate glasses with compositions of xZnO–2xPbO–(1−3x)B2O3 and xZnO–2xPbO–1/2(1−3x)B2O3–1/2(1−3x)SiO2 with x varying from 0.1 to 0.26 mole fraction were prepared by the conventional melt quench technique. Optical and structural properties have been determined by using ultraviolet–visible (UV/vis) and Fourier transform infrared (FTIR) spectroscopic techniques. Decreases in the band gap from 3.57 to 2.62 eV for borate glasses and from 3.00 to 2.35 eV for borosilicate glasses with an increase in the metal oxide content is observed. The density and molar volume has also been measured. Increases in density from 3.994 to 6.339 g cm−3 for borate and from 4.221 to 6.548 g cm−3 for borosilicate glasses are observed with an increase in metal oxide (PbO, ZnO or PbO+ZnO) content. Changes in the atomic structure with composition are observed due to the formation of BO4− units.

Effect of Nd3 + concentration on the physical and absorption properties of sodium-lead-borate glasses

The effect of increasing the rare earth ion concentration on the physical and spectroscopic properties of Nd3 + doped sodium-lead-borate glasses have been studied for the compositions (10-x) Na2O-30PbO-60B2O3-xNd2O3, where x = 1.00, 1.25, 1.50, 1.75 and 2.00 mol %. Optical band gaps, cut-off wavelengths and various spectroscopic parameters (E1, E2, E3, F2, F4, F6 and x4f) have been determined from the room temperature absorption spectra. Judd-Ofelt theory has been employed to determine the intensity parameters W2, W4 and W6 which in turn are used to evaluate radiative transition probability (A), branching ratio (b) and radiative lifetime (tR) for the fluorescent level 4F3 / 2. The W2 parameter and hence the non-symmetric component of electric field acting on Nd3 + ion is found to be highest for glass with 1.75 mol% of Nd2O3. Because of the poor resolution of hypersensitive transition, the covalency of the Nd-O bond has been characterized by the relative intensity of 4I9 / 2 ®4F7 / 2, 4S3 / 2. The highest covalency has been predicted for glass with 2 mol% Nd2O3. The radiative properties are found to improve with an increase in concentration of Nd2O3 for the present study.

Photon interaction studies with some glasses and building materials

Abstract Mass attenuation coefficients of some shielding materials, namely, Bakelite, black cement, white cement, plaster of paris, and concrete were determined at 356-, 511-, 662-, 1173-, and 1332-keV energies, and those of glasses containing oxides of B, Cd, Pb, and Bi were determined only at 662 keV using a narrow beam transmission method. These coefficients of glasses were then used to determine their interaction cross sections, effective atomic numbers, and electron densities. Good agreement was observed between the experimental and theoretical values. It has been proven that glasses have a potential application as a transparent radiation shielding.

Lead- and Bismuth-Borate Fly-Ash Glasses as Gamma-Ray-Shielding Materials

Abstract Values of the gamma-ray mass attenuation coefficient for fly-ash glasses in the system: xBi2O3-0.2B2O3-yFly Ash and xPbO-0.2B2O3-yFly Ash (x = 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.40 and y = 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40) have been determined experimentally at 81-, 356-, 511-, 662-, 1173-, and 1332-keV photon energies using a narrow-beam transmission method. These coefficients of glasses are then used to determine their interaction cross sections, the photon mean free path, effective atomic numbers, and the electron densities. Results have indicated that these fly-ash glasses have potential applications in low-energy gamma-ray shielding.