Depth-dose distribution measurements and calculations in an elliptical phantom

Calculations and measurements are presented for the dose distribution in a water-filled elliptical phantom when the phantom was irradiated with neutrons from two different, unshielded light-water moderated reactors. The calculations were performed by a Monte Carlo code; for the measurements we used activation, TL and solid-state nuclear track detectors. We observed that the neutron spectra do not vary significantly inside the phantom and that not only the total absorbed dose but also the kerma value at a depth of approximately 2 cm can be higher than that on the front (in our case, by a factor of about 1.2). The measurements and calculations resulted in a kerma attenuation from the front to the back of the phantom a factor of about 5, less than was previously known through the literature.