Alanine films for EPR dosimetry of low-energy (1–30 keV) X-ray photons

Abstract

L-α-alanine has aroused considerable interest for use in radiation EPR dosimetry and has been formally accepted as a secondary standard for high-dose (kGy) and transfer dosimetry of high-energy photons and electrons. In this work, we extended the investigation of the energy response of alanine EPR films in the low energy range for X-photons (1-30 keV). Electron Paramagnetic Spin Resonance (EPR) measurements were performed on Kodak BioMax alanine films exposed to low-energy X-rays from a Cu-, Wand Mo-targets tube operating at voltages up to 30 kV. Films were chosen because of the low penetration of the soft X-rays used. The response of alanine to low-energy X-rays was characterized experimentally and the relative response (with respect to high energy photons) was found to be between 0.8 and 0.9 for Cu-and Wtube X-rays, and 1.0 for Mo-tube X-rays. The attenuation profiles were investigated and it was found that 1 mm of film material reduces the intensity of the X-ray-beam by about 70%, 50% and 40% for Cu-, Wand Mo-tube X-rays, respectively. Monte Carlo simulations were performed to model the energy release as well as the depth dose profiles for the various radiation beams used. These data are considered relevant