Measuring the energy spectrum of neutrons produced by 70 MeV protons in a thick aluminium target

Method is described and results are presented of measurements of the energy spectrum of neutrons, produced by protons of the extracted beam of the U-240 isochronous cyclotron. The proton energy was 70 MeV. The aluminium target was thick in comparison with 70 MeV proton range in aluminium, that permitted to exclude the effect of scattered in the target protons on neutron detectors. The neutron spectrum was measured in the energy range of 0.5 eV -55 MeV by the neutron-activation and time-of-flight methods. 8 refs.; 2 figs.; 1 tab