Calculation of neutron production from the polythene moderator of neutron detector when used in mixed field

Betatrons and linear accelerators are in use for cancer therapy around the world, replacing Teletherapy machines of cobalt and cesium because of their advantages like they generate x ray of high energy with sharper delineation, gives high radiation output and even can be used in Electron mode to generate electron beams of specified energy. In India, a large number of high-energy machines, with photon energies higher than 10 MeV are coming into routine clinical use for radiotherapy, because of the improved dose distributions for deep-seated tumors. The great advantage of this equipment is not having a radioactive source attached, which makes them safer from radiological point of view