Studies on effective atomic numbers, electron densities and mass attenuation coefficients in Au alloys

Shielding features of seven types on natural quartz

The shielding features of amethyst, chalcedony, crystal rock, milky, pink, flint, and jasper quartz were calculated. The seven varieties of quartz were collected within the territory of the state of Zacatecas in Mexico. Shielding characteristics include the linear attenuation coefficients, the effective atomic numbers and the mass interaction coefficients for 1 keV to 100 GeV photons. The interaction coefficients were calculated for the coherent scattering, the photoelectric absorption, the Compton scattering, and the pair production occurring in the electric field of the atomic nucleus and the electrons. The linear attenuation coefficients were compared with those of the Portland concrete widely used as radiation shielding. In the low energy region where the photoelectric absorption is dominant the mass interaction coefficients and the total linear attenuation coefficients have three resonances due to the Si, Ca and Fe concentration, these resonances are also noticed in the effective atomic number. For photons below 60 keV the shielding performance of quartz can be used to shield X-ray devices working with less than 60 kV.

Effective atomic numbers of some tissue substitutes by different methods: A comparative study

Effective atomic numbers of some human organ tissue substitutes such as polyethylene terephthalate, red articulation wax, paraffin 1, paraffin 2, bolus, pitch, polyphenylene sulfide, polysulfone, polyvinylchloride, and modeling clay have been calculated by four different methods like Auto-Z_eff, direct, interpolation, and power law. It was found that the effective atomic numbers computed by Auto-Z_eff, direct and interpolation methods were in good agreement for intermediate energy region (0.1 MeV < E < 5 MeV) where the Compton interaction dominates. A large difference in effective atomic numbers by direct method and Auto-Z_eff was observed in photo-electric and pair-production regions. Effective atomic numbers computed by power law were found to be close to direct method in photo-electric absorption region. The Auto-Z_eff, direct and interpolation methods were found to be in good agreement for computation of effective atomic numbers in intermediate energy region (100 keV < E < 10 MeV). The direct method was found to be appropriate method for computation of effective atomic numbers in photo-electric region (10 keV < E < 100 keV). The tissue equivalence of the tissue substitutes is possible to represent by any method for computation of effective atomic number mentioned in the present study. An accurate estimation of Rayleigh scattering is required to eliminate effect of molecular, chemical, or crystalline environment of the atom for estimation of gamma interaction parameters.