Measurements of Secondary Neutrons Produced from Thick Targets Bombawrded by High-Energy Helium and Carbon long

摘要

The angular and energy distributions of neutrons produced by 100 and 180 MeVucleon He and 100, 180, and 400 MeVucleon C ions stopping in thick C, Al, Cu, and Pb targets were measured using the Heavy-Ion Medical Accelerator in Chiba of the National Institute of Radiological Science (NIRS), Japan. The neutorn spectra in the forward direction have broad peaks of ～60 to 70/100 of the incident particle energy per nucleon due to the brak-up process, and they spread up to almost twice the projectile energy epr nucleon. The neutron spectra are similar for the samei n cident energy of 100 MeVucleon for both He and C ions. The phenomenological hybrid analysis, based on the moving source model and the Gaussian fitting of the brak-up process, could well represent the measured thick target neutron spectra.