RT - Journal Article
T1 - A polynomialâ€“based function approach to point isotropic gamma-ray buildup factor data in double layered spherical shield of water and lead
JF - IJPR
YR - 2014
JO - IJPR
VO - 13
IS - 4
UR - http://ijpr.iut.ac.ir/article-1-874-en.html
SP - 383
EP - 389
K1 gamma ray
K1 layer of water
K1 layer of lead
K1 exposure buildup factor
K1 MCNP code
AB - As 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).
LA eng
UL http://ijpr.iut.ac.ir/article-1-874-en.html
M3
ER -