Electron Depth-Dose Distribution Measurements in Finite Polystyrene Slabs

Abstract

Experimental depth‐dose curves for 2.00‐MeV electrons incident on layers of polystyrene were obtained for broad‐beam geometry as a function of slab thickness and incident beam angle. Calibrated radiochromic dye films were used as dosimeters. Continuous spatial absorbance changes in the irradiated film were recorded with the aid of a scanning densitometer. Data were obtained for the following conditions: (a) polystyrene thicknesses 0.42, 0.63, and 1.5 times the electron range, and (b) electron‐beam incidence angles of 0°, 15°, 30°, 45°, 60°, and 75° to the normal. Comparisons were made with theoretical depth‐dose histograms generated by the Monte Carlo computer code ETRAN. Close agreement was found for the two thicker slabs, but energy absorption in the thin slab was observed to be lower than that predicted by the calculations by 5–15%.