Theoretical and experimental radiation effectiveness of the free radical dosimeter alanine to irradiation with heavy charged particles

Dose-response characteristics have been measured for the crystalline amino acid L-.alpha.-alanine irradiated with ion beams of 6 and 16 MeV protons, 20 MeV .alpha. particles, 21 MeV7Li ions, 64 MeV16O ions, and 80 MeV32S ions. The experimental radiation effectiveness (RE) with reference to low-LET radiations of 60Co .gamma. rays, 4 and 16 MV X rays, and 6, 10, and 20 MeV electrons was compared with theoretical RE values derived from a model based on track structure theory of heavy charged particles. The ion beams covered a range in initial LET of 27-20,200 MeVcm2/g, and the experimental RE decreased with increasing LET being 1.00 for 16 MeV protons and 0.25 for the 80 MeV 32S ions. The calculated Re values were in acceptable agreement with the experimental results having a maximum deviation of 8% for the 7Li and 32S ions.