ISSN: 0975-8585 July– August 2015 RJPBCS 6(4) Page No. 1830 Research Journal of Pharmaceutical, Biological and Chemical Sciences Study of Gamma Ray Attenuation of High-Density Bismuth Silicate Glass for Shielding Applications. Aly Saeed a , YH Elbashar b* , and SU El Kameesy c . a Basic Science Department, Faculty of Engineering, Egyptian-Russian University-Cairo, Egypt. b Department of Physics, Faculty of Science, Aswan University, Aswan, Egypt. c Department of Physics, Faculty of Science, Ain Shams University, Cairo, Egypt. ABSTRACT High density glass samples with a chemical formula of xBi 2 O 3 -30SiO 2 –10B 2 O 3 –20BaO-(40−x)ZnO (where x= 0, 10, 20, 30, and 40 mol %) were prepared using the melt-quenching technique in order to design a new transparently shielding materials for many fields of applications. The amorphous state of the samples was examined using X-ray diffraction technique at room temperature. The effect of bismuth on the structural properties of the studied glasses was characterized through density and its derivative parameters. Before measuring the attenuation capability, the optical transparently for visible light were tested using the transmittance spectra measurements in the UV-Visible region. Optical parameters such as optical band gap, Urbach energy, and refractive index were evaluated from the optical data. The Gamma ray attenuation coefficients of the glass samples were performed at gamma ray energies 238.63, 338.28, 583.19, 911.20, 968.97, 1173.23, 1332.49, and 2614.51 keV that emitted from 232 Th and 60 Co radioactive sources. The transmitted gamma rays were detected using Hyper Pure Germanium detector (HPGe) under good geometry conditions. The Linear attenuation coefficients were deduced from the attenuation curves and then the mass attenuation coefficients and the half value layer were estimated. Theoretical mass attenuation coefficients were calculated using WinXCom program (version 3.1). A good correlation was observed between the experimentally determined and those computed theoretically of the mass attenuation coefficients. Keywords: Radiation shielding materials, optical transmittance, lead free glass. *Corresponding author