Energy Absorption and Exposure Buildup Factors in Polymers by Nuclear Track Detectors

摘要

The photon mass attenuation and mass energy absorption coefficients, energy dependence, effective atomic number, effective electron density and buildup factors are the fundamental quantities required in determining the penetration of X-rays and 7-photons through the material. These parameters have been examined for different polymers by nuclear track detectors. The effective atomic number was found in the range of 6 < Z_(PIeff) and Z_(peaeff) < 8 atomic number of their constituent elements for selected polymers. Effective electron density values show similar photon energy dependence to what has been observed for Z_(eff). The maximum values of energy absorption buildup factor and exposure buildup factor have been observed at 0.08 and 0.1 MeV, respectively. The significant variations in energy absorption buildup. factor and exposure buildup factor for polymers have been observed at the moderate energy region. Besides, effect of variations in chemical composition of the given materials has also been observed to the energy absorption buildup factor and exposure buildup factor values. At energies below 0.15 MeV, energy absorption buildup factor and exposure buildup factor values increase with decreasing Z_(eq), of the samples. At 1.5 MeV, where only Compton scattering is the dominant interaction process, values of energy absorption buildup factor and exposure buildup factor seem to be independent of chemical composition of the polymers. It has been concluded that the buildup of photons is less in cellulose nitrate when compared with other materials.