Damage effects of gamma and X-rays in polymer film electrets

Abstract

Dosimeters produced with electret materials are able to detect X-rays, α, β, γ rays, electrons and other charged particles and, with appropriate converters, fast and slow neutrons. To produce and use an electret dosimeter, the polymer must be charged using a system that is able to inject an initial charge into the electret material. After charging, it can be exposed to ionizing radiation and the remaining electret charge density can be read with the help of an appropriate device, for radiation dosimetry estimation. In this work we have charged and exposed PFA (tetrafluoroethylene-per-fluoromethoxyethylene) and FEP (tetrafluoroethylene-hexa-fluoropropylene) polymeric films to various radiation absorbed doses using 60Co gamma rays (1.25 MeV) and X-rays (0.106 MeV). In order to identify damage that can compromise the use of these materials as dosimeters, the virgin, charged and exposed films were analysed with Optical Absorption Photospectrometry (OAP), Fourier Transform Infrared (FTIR) and Micro-Raman spectroscopy. The analysis results are shown to demonstrate the damage caused by these radiation sources in the polymers.