LAUSR

Abstract Ionization chambers are often used in a phantom of material different from their walls, leading to a fluence perturbation. The main goal of this paper is to investigate the water equivalence of some polymers used for construction of ionization chamber’s wall and phantoms. To accomplish this goal, a Monte-Carlo model was used to calculate the depth dose as well as radiation-interaction parameters for mono-energetic photons (20–100 keV) and spectrum of 50–100 kVp X-rays. For mono-energetic photons, the maximum difference between the simulation results and theory was 2.4%. Plexiglass and RW3 had similar water equivalence and transmission properties as compared to water to within ±3.2%. Their depth doses were almost identical (to within 2.80%). The largest difference in depth dose compared to water found at 50 kVp. The dosimetric agreement was improved with increasing the X-ray energy, so that the maximum deviation was 6.3% for 100 kVp X-rays.