Seminar: The LANL C‐NR Counting Room and Fission Product Yields

Dr. Kevin Jackman, Los Alamos National Laboratory

All dates for this event occur in the past.

E141 Scott Lab
E141 Scott Lab
201 W. 19th Ave.
Columbus, OH 43210
United States

Abstract

The Counting Room of the Nuclear and Radiochemistry Group (C-NR) at Los Alamos is a 24/7 facility for the quantitative assay of radionuclides that dates back to the Manhattan Project. Current analysis techniques employed include alpha spectrometry, beta counting, gamma-ray spectrometry, liquid scintillation counting, and X-ray spectrometry. A brief overview and history of the Counting Room facility is presented. Past and present research regarding the measurement of fission product yields and the nature of the two-mode fission hypothesis is discussed. The two-mode fission hypothesis suggests two general modes, asymmetric and symmetric, for the fission process at low and high excitation energies respectively. The relative proportion of each mode changes as a function of excitation energy, and produces different fission product mass-yield distributions for a given target nuclei. The hypothesis also predicts linear relationships between pairs of fission product yields, which agree well with experimental observations. This talk also includes some elucidating findings in the resonance region from the “neutron wheel” experiments conducted by Los Alamos in the early 1960’s. The relevance of the energy dependence of fission product yields to post-detonation nuclear forensics is presented.

About the Speaker

Kevin R. Jackman is a Technical Staff Member on the Counting Rooms team in the Nuclear and Radiochemistry (C-NR) Group at Los Alamos National Laboratory (LANL). He routinely performs analysis of radioactive materials and helps maintain, operate, and upgrade radiation detector instrumentation in support of nuclear forensics, debris analysis, isotope production, and environmental monitoring programs. He currently designs and conducts experiments to measure integral actinide cross-sections and fission product yields at the Nuclear Criticality Experiments Research Center (NCERC) in support of several nuclear non-proliferation projects. He is engaged in studying the energy of dependence of fission product yields in different materials. He has been an analyst member on the NNSA/DOE Forensics Operations (DFO) field team since 2011. From 2008 to 2010, he served as te lead scientist for the Defense Threat Reduction Agency / Pacific Technical Support Group (PTSG). He has extensive experience in gamma-ray spectrometry, radiation detector design, coincidence counting, computer programming and simulation. He obtained a Ph.D in 2007 and a M.S. in 2004, both in Mechanical Engineering (Nuclear and Radiation Engineering), a B.S. Physics (Radiation Physics) and B.A. Astronomy in 2003 all from University of Texas at Austin.

Hosted by Professor Lei R. Cao