Evaluation of the spatial resolution of the peeled-off Gafchromic EBT2 film irradiated with different doses of low-energy alpha particles from 241Am

Abstract

Abstract In the current study, the edge spread function, the spatial resolution (), and the response of Gafchromic EBT2 film to low-energy alpha particle doses were investigated. The Gafchromic EBT2 films were peeled-off to permit the 4 MeV alpha particles to reach the active layer. The peeled-off Gafchromic EBT2 films were irradiated with different doses of 4 MeV alpha particles from 241Am, where a razor blade was kept in close contact with the active layer in the middle of the alpha particles beam to produce two distinct halves (edges). The measured edge spread function (ESF) for different color channels as well as the weighted and unweighted gray images were fitted using the error function and thereafter differentiated to produce the line spread function (LSF). The blue channel exhibits an anomalous response to the 4 MeV alpha particle dose, leading to a dynamic range reduction of the peeled-off Gafchromic EBT2 film. The pixel values of red and green channels decrease by increasing alpha particle doses, with a descending sensitivity at higher doses. The pixel values of weighted and unweighted gray images decrease with the increase in alpha particle doses but with lower sensitivity. The spatial resolution of the peeled-off Gafchromic EBT2 film is independent of the 4 MeV alpha particle doses for red, green color channels, and weighted and unweighted gray images; the spatial resolution is close to that of single-color channels but with less contrast and visibility. The average spatial resolution, within the same channel, in terms of 1 (standard deviation), amounts to (21.9 ± 1.5), (19.5 ± 1.4), (19.4 ± 1.3), and (19.4 ± 1.3) μm for red and green channels, weighted and unweighted gray images, respectively. Finally, the LSF peak was found to be proportional to the associated absorbed dosage. This can be utilized for forecasting the alpha-particle absorbed dose within the boundaries of the current study.