The Defect Characterization Of Rare-Earth Intensifying Screen Material By Doppler Broadening Positron Annihilation Spectrometer

Doppler broadening spectrometer for positron annihilation experiment(DBPAS) has been used to characterize nano size defect structures in materials. DBPAS measures the concentration, spatial distribution, and size of open volume defects in the rare-earth intensifying screen materials. The screens were exposed by X-ray varying the exposed doses from 3, 6, 9, and 12 Gy with 6 MV and 15 MV, respectively and also irradiated by 37 MeV proton beams ranging from 0 to 1012 ptls. The S parameter values increased as the exposed time and the energies increased, which indicated the defects were generated more. The S parameters of the samples with X-rays varied from 0.5098 to 0.5108, on the other hand, as proton beams varied from 0.4804 to 0.4821.