Science and Education Publishing International Journal of Physics 2333-4886 2 1 2014 03 11 Using Gamma-Ray to Determine the Homogeneity of Some Building Materials 23 29 EN Laith A. Najam Department of Physics, College of Science, University of Mosul, Iraq Ahmed K. Mheemeed Isra.a M. Hassan IJP2014215 10.12691/ijp-2-1-5 2014 02 11 2014 03 07 2014 03 11 In this paper, we use a narrow collimated beam of mono- energetic gamma rays emitted from the radioactive source 137Cs (662 keV) and the system of measuring gamma rays UCS-20 associated with the sodium iodide detector NaI (Tl) to determine the homogeneity of the building materials, Granite, Marble, Cement, Ceramic and Bricks. The homogeneity test was determined from the percentage difference between the transmitted intensity of gamma-rays and the linear attenuation coefficient at different positions for each sample of the material then the percentage of standard deviation was checked.