Investigation of defect production in iron on gamma irradiation using the positron Doppler broadening technique

摘要

The parameters S and W corresponding to the positron Doppler broadening technique have been used to study displacement type defects produced in iron samples irradiated by various imparted doses of gamma ranging from 20 Gy to 2kGy. For the logistic support of the experimental observations, Monte Carlo simulation of displacements has also been performed. Of the increase of S parameter with dose up to a limit, it is revealed that vacancy type defects dominate. From both the experimental observations and the Monte Carlo study, it is inferred that on irradiation monovacancies are produced and under the given irradiation conditions there is negligible chance of the atom+atom collision cascade which may give rise to multiple type vacancies.