Determination of electron fluence ratios for various materials in an electron beam

To determine the electron beam dose at depth of dose maximum (d _max) in a specific phantom material from the dose at d_max in water we need the collision stopping power ratio of the material to water and Φ_water^mat, the ratio of electron fluence at d_max in the material to that of water. We have measured depth doses in solid water, bone, lung, aluminum and copper, irradiated in electron beams with nominal energies 9 and 15 MeV with thermoluminescent dosimetry techniques, The measured relative dose at d_max in the various materials versus that of solid water, when irradiated with the same number of monitor units, has been used to calculate the ratio of electron fluence for the various materials to that of solid water. The results were also verified using Monte Carlo calculations