Development of a U-235m generator for measurement of neutron cross sections

NUCL 146

Dawn A. Shaughnessy, Yves X. M. Dardenne, Kenton J. Moody, Mark A. Stoyer, and John F. Wild. Analytical and Nuclear Chemistry Division, Lawrence Livermore National Laboratory, P.O. Box 808, L-231, Livermore, CA 94551
There is interest by the defense and nuclear technology field in measuring cross sections from 235mU(n,f) reactions. We are currently developing an online 235mU generator in order to produce quantities sufficient for targets in neutron bombardments. The alpha decay of 239Pu populates the 235mU isomer and members of the 235mU-based rotational band almost exclusively (approximately 99.9%.) By using an online production method, a continuous supply of 235mU can be generated with a favorable ratio of 235mU isomer to 235U ground state. The generator consists of a thin layer of 239Pu electroplated on the inside of a tube. The 239Pu layer is thin enough such that 235mU recoil is efficiently emitted into the center of the tube. The recoils are collected in a stream of gas passed through the tube and deposited where needed. Initial tests and optimization of the generator parameters will be discussed.

This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.