www.jocpr.com Available on line Journal of Chemical and Pharmaceutical Research ISSN No: 0975-7384 CODEN(USA): JCPRC5 J. Chem. Pharm. Res., 2011, 3(4): 899-903 899 Measurement of mass and linear attenuation coefficients of gamma- rays of Al for 514, 662 and 1280 keV photons Pravina P. Pawar Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, India ______________________________________________________________________________ ABSTRACT Measurements have been made to determine gamma ray attenuation coefficients very accurately by using a narrow-collimated-beam method which effectively excluded corrections due to small- angle and multiple scattering of photons. Mass (/ρ) and linear attenuation coefficients () of Al for 514, 662 and 1280 keV gamma-rays photons have been measured using the well-type scintillation spectrometer. The values of  and /ρ thus obtained are found to be in good agreement with the theory. Keywords: Mass attenuation coefficients, Linear attenuation coefficients, Gamma-rays. ______________________________________________________________________________ INTRODUCTION The photoelectric effect, the Compton scattering and the pair production processes are the predominant interactions between the photons and atoms apart from other types over a wide range of energies. With wide spread utilization of radiation and radioisotopes in medicine ,industry and basic sciences, the problem of radiation protection has become important aspect while handling radiation sources and radiation generating equipments. Selection of materials for radiation shielding and protection needs accurate assessment of interaction parameters. These parameters are of immense importance for photons being highly penetrating radiation as compared to particulate radiations. A survey of other relevant measurements [1-12] reported shows that in many of these measurements the experimental results for the same elements at the same energies are somewhat