Measurements of thick target neutron yields and shielding studies using beams of 4He, 12C and 16O at 155 MeV/nucleon from the K1200 cyclotron at the National Superconducting Cyclotron Laboratory

Measurements of neutrons from a thick target of Hevimet were made, using beams of 4He, 12C, and 16O ions at 155 MeV per nucleon. These measurements were made both inside and outside of thick concrete shielding, using Bonner-sphere techniques. Yields, spectra, and spectral integral quantities were obtained. The neutron yields were parameterized, and a Moyer-model approach was taken to estimate the dose-equivalent outside of the thick concrete shielding. The effect of local iron shielding, and the dose equivalent outside of iron roof shielding were also investigated. Finally, two methods to obtain neutron field integral values, the 'reconstructed spectra' and 'six-spheres' methods, were compared. The measurements and analyses should prove useful to other present or planned medium-energy heavy-ion accelerator facilities.copyright 1999 American Institute of Physics