Investigation of the physical properties of polymeric materials induced by alpha radiation

CR-39 is an ideal solid-state detector of nuclear radiation, which is frequently used to learn more about cosmic rays, long-standing radioactive elements, radon concentration in houses, and the age of geological samples. The effects of ?-particles on the physical properties (optical properties, electrical properties and the structure) of CR-39 polymer were investigated. The irradiations were performed by using 241Am at constant alpha particle energy 4.86 MeV at normal incident for different irradiation times (6-96) hours. A variation in the optical energy band gap (Eg) values was appeared. This variation suggested formation of defects (radicals and organic species). Moreover, X- ray diffractions were performed on irradiated and non –irradiated CR-39 samples to study the structure of samples. Positron Annihilation Doppler- Broadening technique was used to study the effect of irradiation ?-particles emitted from 241Am (4.86Mev) source on the line shape S- and w- parameters for CR-39 samples. The results showed formation of defects in CR-39 samples after irradiations, and good correlation between S and W parameters with R=0.99 for the sample at irradiation times (6, 24 and72 hrs). In addition a correlation is exists with R=0.72 between the Eg and S-parameter .Extended system of conjugated bonds due to irradiation was noticed. The obtained results were discussed and compared with other literature data; it showed an agreement with these results to some extent.