5-Bev Neutron Cross Sections in Hydrogen and Other Elements

Abstract

This experiment measured the neutron total and reaction cross sections at 5.0 Bev. Transmission measurements were made in good and poor geometry. The high-energy neutron beam was produced when the Bevatron circulating proton beam struck a copper target. Neutrons were identified by their production of pions in a beryllium block. The pions were then detected by a counter telescope including a gas \ifmmode \check{C}\else \v{C}\fi{}erenkov counter. The threshold of this gas \ifmmode \check{C}\else \v{C}\fi{}erenkov counter defined the mean effective neutron energy at 5.0\ifmmode\pm\else\textpm\fi{}0.4 Bev, with the half-intensity points of the neutron energy distribution at 5.9 and 4.2 Bev. The cross sections measured for the various elements are (in millibarns): The 5-Bev total cross sections are 20% below the total cross-sections measured at 1.4 Bev by Coor et al., whereas the reaction cross sections remain essentially constant as a function of energy above 300 Mev. This behavior of the cross sections can be interpreted by a generalized diffraction theory developed by Glassgold and Grieder.