Total Neutron Cross Sections of U233 and U235 from 0.02 to 0.08 ev

Abstract
Neutron transmission measurements of U233 and U235 have been obtained from 0.02 to 0.08 ev. The 2200 m/sec total neutron cross section values have been calculated from a linear least-squares fit to the data in this region and found to be 587 ± 6 and 690 ±10 barns, respectively. The data were taken with the Materials Testing Reactor (MTR) fast chopper with an instrument resolution of 2 µsec/m. Experimental techniques, involving the use of a 1024-channel time-of-flight analyzer for measuring total cross sections at low energies, are described.