IOSR Journal of Engineering (IOSRJEN) www.iosrjen.org ISSN (e): 2250-3021, ISSN (p): 2278-8719 Vol. 04, Issue 02 (February. 2014), ||V7 || PP 01-08 International organization of Scientific Research 1 | P a g e Gamma-Rays Absorption Studies of Garnet series of Gemstones at 1 Kev to 100 GeV: Theoretical Calculation Sandeep Gupta 1 , Gurdeep Singh Sidhu 2 1 (Department of Physics, Faculty of Applied Sciences, Singhania University, Rajasthan-333515, India) 2 (Department of Physics, G.S.S.S., Jodhpur-Romana, Bathinda-151001, India) Abstract: - Mass attenuation coefficients and partial photon interactions have been calculated theoretically at incident photon energy 1 Kev to 100 GeV for garnet series of gemstones (Grosaularite (GS1), Pyrope(GS2), Spessarlite(GS3), Almandine(GS4), Uvarovite(GS5) and Androdite(GS6) using XCOM software [1]. The values of these parameters have been found to change significantly with incident photon energy and composition of the garnet series of gemstones. Half value layer (HVL) and tenth value layer (TVL) has also been calculated; whose lower value reveals the good shielding ability for gamma rays. Hence it is concluded that GS4 shows the maximum shielding effectiveness and also GS6 and GS3 seem to have good radiation shielding. It is also analyzed that our calculated mass attenuation coefficient of NBS concrete by the present method are in excellent agreement with standard values given by ANSI/ANS-6.4.3 data. Keywords: - Gemstones, Half value layer, Mass attenuation coefficients, and Tenth value layer. I. INTRODUCTION Radiation protection is necessary, because radiation is all around us, in the air, the water, the food we eat. It causes us to feel unwell, and it can contribute to the eventual onset of disease. That’s why we need effective ways of protecting ourselves from this bombardment. And nature has provided a ready-made solution. Gemstone and noble metal combinations in jewelry are far superior technology for protection from radiations. Gems need to be worn in contact with the skin, and the larger the surface area in contact the better. In today’s world, irradiation is routinely used to color a number of gemstones. The process by which irradiation changes color is fairly straightforward. Radiation causes electrons to be knocked off some atoms, leaving them free to be absorbed by others. This has the effect of creating “color centers” which in turn alter the light-absorbing pattern of the gemstone and by extension its color. Generally it is gamma rays from radioactive elements such as cobalt which labs use to irradiate gemstones. Gamma rays leave no residual radioactivity. Radium by contrast, does and is hence dangerous to human health[2]. Garnet series gem stones are good materials which are at low cost and easily available and protect from radioactive radiations. The study of absorption of gamma rays in the gem stones has become an interesting and exciting field of research. The photon mass attenuation coefficients are the basic quantities required in determining the penetration of X-rays and gamma photons in matter [γ]. The mass attenuation coefficient (μ/ρ) is a measure of probability of interaction that occurs between incident photons and matter per unit mass per unit area. The knowledge of mass attenuation coefficients of X rays and gamma photons in biological, chemical and other important materials is of significant and practical interest for industrial, biological, agricultural, defence and medical applications [4]. Accurate values of photon mass attenuation coefficients are required to provide essential data in diverse fields such as nuclear diagnostics (computerized tomography), nuclear medicine, radiation protection, radiation dosimetry, gamma ray fluorescence studies, radiation physics, shielding, security screening and etc[5]. The mass attenuation coefficient values of partial photon interaction processes such as photoelectric effect, Compton scattering, pair production and total are available in the form of software package XCOM from Berger and Hubbell [6, 7] by substituting the chemical composition/weight fraction of compound/mixture, the mass attenuation coefficient of the shielding materials will be generated in the energy range 1 Kev - 100 GeV [8]. Hubble are published tables of mass attenuation coefficients and the mass energy absorption coefficients for 40 elements and 45 mixtures and compounds for 1 keV to 20 MeV in 1982.Hubbell and Seltzer replaced these tables in form of tabulation for all elements having 1 ≤ Z ≤ 9β and for 48 additional substances for dosimetric interest [9]. The reports on attenuation coefficients measured by researchers reported [8-19] for different energies for various samples in solid, liquid, stones and alloys. ANSI/ANS-6.4.3 (1991) standard has been administratively withdrawn in August 2001, but the work is in progress for updating this much used standard by a working group chartered in 2007 by the American Nuclear Society (ANS). Recently, a study has been made for the purpose of updating gamma-ray mass attenuation coefficients for high-Z engineering materials that are presented in the current ANS standard [3].This