انجمن فیزیک ایران
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دانشگاه صنعتی اصفهانمجلۀ پژوهش فیزیک ایران1682-695713420191126A polynomialâbased function approach to point isotropic gamma-ray buildup factor data in double layered spherical shield of water and leadاستخراج ضریب انباشت تابشهای گاما به صورت تابع چند جملهای در حفاظهای کروی دولایهای (آب – سرب)3833891056FAمحمدحسنعلامت سازمریم الساداتمحسنیJournal Article20191126As the input of MCNP code (Monte Carlo N - Particle code system), a monoenergetic and isotropic point source with the energy rangeg from 0.3 to 10 MeV was placed at the center of a spherical material surrounded by another one. The first shielding material was water and the second one was lead. The total thickness of the shield varied between 2 to 10 mfp. Then, using the output of MCNCP, exposure build up factor was calculated. The MCNP computed data were analyzed by plotting the buildup factor as a function of each independent variable (energy, first material thickness and second material thickness) and observing the trends. Based on the trends, we examined many different expressions with different number of constants. By MINUIT the FORTRAN program, the constants were calculated, which gave the best agreement between the MCNP-computed exposure buildup factors and those obtained by the formula. At last, we developed a polynomial formula with 11 constants that reproduced exposure buildup factor with a relative error below 2% (in comparison with the MCNP result).https://ijpr.iut.ac.ir/article_1056_b1807d203bdbd18708c601668a5f2df8.pdf