NIST Standard Reference Database 126 Last Update to Data Content: July 2004 NISTIR 5632 DOI: Tables of X-Ray Mass Attenuation Coefficients and Mass Energy-Absorption Coefficients from 1 keV to 20 MeV for Elements Z = 1 to 92 and 48 Additional Substances of Dosimetric Interest* J. Hubbell + and Radiation Physics Division, PML, NIST © 1989, 1990, 1996 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

NIST reserves the right to charge for these data in the future. Abstract Tables and graphs of the photon mass attenuation coefficient μ/ ρ and the mass energy-absorption coefficient μ en/ ρ are presented for all of the elements Z = 1 to 92, and for 48 compounds and mixtures of radiological interest. The tables cover energies of the photon (x-ray, gamma ray, bremsstrahlung) from 1 keV to 20 MeV. The μ/ ρ values are taken from the current photon interaction database at the National Institute of Standards and Technology, and the μ en/ ρ values are based on the new calculations by Seltzer described in Radiation Research 136, 147 (1993). These tables of μ/ ρ and μ en/ ρ replace and extend the tables given by Hubbell in the International Journal of Applied Radiation and Isotopes 33, 1269 (1982). Table of Contents • • Material constants for elemental media. Material constants and composition for compounds and mixtures.

Values of the mass attenuation coefficient and the mass energy-absorption coefficient as a function of photon energy, for: [Data] elemental media. [Data] compounds and mixtures. • • • *Work supported by the of NIST. +Work carried out for NIST under contract 43NANB412756. NIST Standard Reference Database 126  Online: May 1996  Last update: July 2004.

Title: WinXCom—a program for calculating X-ray attenuation coefficients. Authors: Gerward, L.; Guilbert, N.; Jensen, K. B.; Levring, H. Affiliation: AA(Department. A Windows version of XCOM, the well-known program for calculating X-ray and gamma-ray attenuation coefficients and interaction cross sections, has been developed. The new program, called WinXCom.

(4) w i = n i A i ∑ i n i A i Where, A i is the atomic weight of the sample, n i is a number of formula units. Validation Applying the Monte Carlo method is the one of the best solution for the investigation of different complex material behaviors since experimental duplication of investigation is quite complicated. So, it is more suitable to apply some numerical methods such as Monte Carlo [ 12]. In this paper, a validation for input code was performed. On the other hand, WinXcom program was also used to calculate the gamma ray mass attenuation coefficients of the studied shielding materials. WinXcom [ 13, 14] program is a user friendly calculation program and input parameter specifications are quite flexible and easy to access. In the WinXcom program, firstly, shielding material types were defined by their elemental mass fractions, which are totally the same as in MCNPX Monte Carlo code input.

Secondly, the gamma ray energies have been defined. The attenuation coefficients of the selected materials were finally calculated by the program. Results and Discussion MCNPX simulation input has been used for mass attenuation coefficients calculations of cement, gypsum and the mixture of gypsum and PbCO 3 materials. The mass attenuation coefficients for attenuator samples doped by different percentages of PbCO 3 were calculated for the four different energies 356, 662, 1,173, and 1,333 keV and shown in Figure 2. The standard XCOM data has been used for comparison with obtained MCNPX results. Figure 2 shows mass attenuation coefficinents of cement, gypsum and small doping of PbCO 3 in both the shielding materials. It is found that the mass attenuation coefficients of pure and doped cement or gypsum are decreasing with increase in photon energy.