The Measurement of the Neutron-induced Fission Cross Section of 240Am

Paul Ellison, University of California, Berkeley


The measurement of the neutron-induced fission of 240Am is of particular interest because of its role as a radiochemical diagnostic tool to measure the neutron fluence of a nuclear device. One of the major obstacles in the measurement of this cross section is the production of a substantial enough quantity of 240Am because of its 50.8 hour half-life. This work focuses on the production of 240Am at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory through the proton bombardment of 242Pu via the three neutron evaporation exit channel, a previously unreported nuclear reaction. Separation procedures are being developed to purify the americium formed in this reaction from the plutonium target material and the inevitable reaction fission products. Once we have developed the production reaction and separations procedure, we will produce 240Am on the scale of 10 nanograms to be irradiated at the Lead Slowing-Down Spectrometer at the Los Alamos Neutron Science Center.

Abstract Author(s): Paul A. Ellison and Heino Nitsche University of California, Berkeley, Department of Chemistry and Lawrence Berkeley National Laboratory, Nuclear Science Division