NEUTRON ENERGY DEPOSITION SPECTRA AT SIMULATED DIAMETERS DOWN TO 50 NM

A special cylindrical tissue-equivalent proportional counter has been designed and constructed. Using a recently developed calibration techn ique with Ar-37, its performance has been analysed for simulated sites with diameters down to 100 nm. Neutron energy deposition spectra have been obtained for simulated diameters 50-2000 nm with neutron beams f rom the H-2(d,n)He-3 reaction. The peak at high energies imparted due to heavy particle recoils and the proton edge are clearly seen in the spectra even at the smallest simulated diameters.