Study of neutron energy spectra by a multisphere spectrometer

Results of experimental investigations into the possibilities of a multisphere spectrometer to solve reactor shielding problems are presented. Neutron spectra of the 238Pu-10B, 238Pu-LiH, 238Pu-F, 239Pu-Be, 252Cf, Ra-Be homogeneous sources and the sandwich type 238Pu-Be heterogeneous source are measured. Neutron spectra in a sodium cooled fast reactor piping mockup are also measured. Neutron spectra of the ''RIZ'' reactor behind a cylindrical shielding from Al, Fe, graphite and polyethylene of finite dimensions have been investigated. Multisphere spectrometers are concluded to provide an opportunity to get an approximate but rather reliable estimation of neutron spectra in a wide energy range (10-1-107 eV). The accuracy of the estimation increases if a set of spectrometers is used: scintillation, multishere spectrometer and that with a hydrogen containing proportional counter