On possibility of using superfast neutrons for radiotherapy on the basis of high-current proton accelerators

Calculation data on depth distribution of full absorbed dose and its components for the case of normal neutron drop with 60 MeV and 200 MeV energies on half-infinite tissue-equivalent medium of 30 cm thickness are given. Relations of absorbed doses at the tissue depth of 10-15 cm to the dose on the surface, as well as data on average values of the linear energy transfers for neutrons of different energies are presented. It is shown that from the view point of therapy of deep-laying tumours the superfast neutrons are more advantageous as compared not only to rare ionizing irradiation, but to fast neutrons (14-20 MeV), which are considered perspective in modern therapy, as well. It is shown, that heavy-current accelerator of protons of ''meson factory'' type can be used as the neutron source with the energies up to 160 MeV with intensities enough for beam therapy. Be, Li, Al, Cu can be used as a target for production of superfast neutrons. Calculations have shown, that at the distance of 5 m from the target at 100 μA current of 70 MeV protons the dose rate can constitute 25-36 rad/min