Accelerator based epithermal neutron source for NCT

Nowadays neutron capture therapy looks very promising method of cancer treatment, especially for brain tumors by reason of selective damage cancer cells. Treatment effect of this method based on neutrons nuclear reaction with nuclides B, Gd. These nuclides have high cross-section of interaction with thermal neutrons. Unfortunately, thermal neutrons could enter only in near surface tissue and could not be used for deep localized tumors. This restriction limit such neutrons using only for surface tumors or for intraoperative therapy. For deep situated tumors looks more prospective to use epithermal neutrons with energy from 1 eV to 10 keV. These neutrons have much more penetrative ability and slow down in tissue till thermal energy. It makes possible neutron capture therapy for tumors located on depth up to 10 cm from surface. Important, that in epithermal neutron beam amount of fast neutrons must be as small as possible, because of dose from high-energy neutrons is main factor limited treatment process. Main critical factor is surface absorbed dose form reaction with fast neutrons. For treatment purposes necessary to have epithermal neutrons beam with size about 10x10 cm and neutron flux ~10 s -1 cm .