Neutron and gamma penetrations through and behind BeO were measured. Neutron spectra measurements by threshold foil techniques indicated practically no change in the fast-neutron spectrum above 2.5 Mev in BeO. Thus, beryllium appears to lie in the transition region between the very light elements that harden a fission spectrum and the heavier elements that soften it. The ratio of fast-neutron fluxes below and above 2.5 Mev increased rapidly with distance through the BeO. Information indicated that the flux peaked at around 1.5 to 2.5 Mev. In this energy range the scattering cross section of beryllium goes through a minimum. Fast …
continued below
Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.
Descriptive information to help identify this report.
Follow the links below to find similar items on the Digital Library.
Description
Neutron and gamma penetrations through and behind BeO were measured. Neutron spectra measurements by threshold foil techniques indicated practically no change in the fast-neutron spectrum above 2.5 Mev in BeO. Thus, beryllium appears to lie in the transition region between the very light elements that harden a fission spectrum and the heavier elements that soften it. The ratio of fast-neutron fluxes below and above 2.5 Mev increased rapidly with distance through the BeO. Information indicated that the flux peaked at around 1.5 to 2.5 Mev. In this energy range the scattering cross section of beryllium goes through a minimum. Fast neutron dose measurements through BeO were compared with those calculated by the moments method. The removal cross section for BeO was determined from fast-neutron dose rates measured in the water behind the slabs. Gamma dose rates were measured through and be hind the BeO slabs with a carbon chamber. The gamma dose rate decreased with a relaxation length of about 11 cm near the source. The relaxation length increased with distance through BeO, indicating spectrum hardening. Gamma spectra were measured at intervals behind BeO slabs with a collimated sodium icdide crystal. The 6.8 and 3.41 Mev beryllium capture gamma rays became dominant as the distance through the BeO increased. Thermal flux was measured through and behind the BeO with both a fission chamber and gold foils. Thermal flux distributions for these tests were calculated by a multilevel diffusion code. The calculations differ from the experiment at large penetration distances through BeO. (auth)
This report is part of the following collection of related materials.
Office of Scientific & Technical Information Technical Reports
Reports, articles and other documents harvested from the Office of Scientific and Technical Information.
Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.
Klingensmith, Raymond W.; Jung, Richard G.; Lindgren, William A.; Epstein, Harold M. & Chastain, Joel W., Jr.FAST-NEUTRON AND GAMMA SPECTRUM AND DOSE IN BERYLLIUM OXIDE,
report,
January 11, 1961;
United States.
(https://digital.library.unt.edu/ark:/67531/metadc1054096/:
accessed April 25, 2024),
University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu;
crediting UNT Libraries Government Documents Department.
