In the past few years, there has been a considerable increase in the use of high energy accelerators in radiotherapy. One of the problems encountered in room design for housing such accelerators is the lack of information in the literature about shielding parameters in the energy range above 10 MeV. In this study, the 25-MV X-rays from an Allis-Chalmers Betatron and a Thompson-CSF Sagittaire Linear Accelerator were studied comparatively. Unreinforced concrete slabs (2.26 g/cm3) and a modified cutie pie chamber in a water tank connected to a Keithley electrometer were used. Transmission of the primary beams (narrow and broad beam geometries), transmission of secondary radiation at different angles from an Alderson Phantom, variation of 10th-value-layer with field size, scatter angular distribution, and neutron transmission in concrete are presented.
©1975Health Physics Society