A simple one-dimensional model for understanding planar dose-versus-depth profiles in mixed photon/electron fields.
A one-dimensional model is described for illustrating the perturbing effects of mixed photon/electron fields on planar dose-versus-depth profiles in low Z materials (Z < or = 20), and at moderate photon energies (0.3-10 MeV). An electron field may arise from photon interactions in filters upstream of a dose-versus-depth experiment. The effects of upstream mass, scattering of electrons out of a gap between a filter and the experiment, and differences between the incident electron energy distribution and locally produced KERMA are modeled and compared to Discrete Ordinates calculations. At transitional depths in a dose-versus-depth experiment, the distortions can be significant and obscure the profile of the photon component alone.
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Department 1277, Sandia National Laboratories, Albuquerque, New Mexico 87185.
D055592:Biophysical Phenomena; D001703:Biophysics; D004583:Electrons; D008962:Models, Theoretical; D017785:Photons; D011829:Radiation Dosage; D012542:Scattering, Radiation