Comparison of graphite calorimeter dosimetry system with Monte Carlo simulation at an industrial electron beam accelerator

In a previously published study, we reported the estimation of various dosimetry parameters such as average absorbed dose, energy fluence and practical range for an electron beam of 1.6 MeV using graphite calorimeters of different thicknesses. In this study, depth dose distribution in a graphite block was measured using cellulose triacetate (CTA) dosimeter strip for the scanned electron beam of kinetic energy 1.6 MeV and compared against the EGSnrc-based Monte Carlo calculations. Monte Carlo calculations agree to the measurements for depths beyond about 0.15 cm. Similarly absorbed dose measurements were carried out in graphite discs of different thicknesses and compared against the Monte Carlo calculations. The comparison is good for thicknesses of discs 0.4 cm and above. Although, the disagreement between measurements and calculations does not affect overall conclusion of the study, disagreement is attributed possibly due to presence of low energy spectrum of electrons in the measurements in addition to the prominent 1.6 MeV electrons. Both calculations and measurements demonstrate that energy absorption is linear up to 0.3 cm thick graphite. (C) 2012 Elsevier B.V. All rights reserved.