NUCLEAR AND CHEMICAL SCIENCES DIVISION, LLNL
PHYSICS DEPARTMENT, UC DAVIS
For many years, the state of the art for treating fission in radiation transport codes has involved sampling from average distributions. In these average fission models energy is not explicitly conserved and none of the outputs are correlated because all particles (fission fragments, neutrons and photons are considered) are emitted independently. However, in a true fission event, the energies, momenta and multiplicities of the emitted particles are correlated. Such correlations are interesting for many modern applications. Event-by-event generation of complete fission events retains information for all particles emitted, making it possible to extract any desired correlation observable. These complete event simulations can be included in general Monte Carlo transport codes. In this talk, the types of available data for model input and validation are presented. The physics of one such complete event fission simulation code, FREYA, is described in some detail. Comparison is then made between some currently available phenomenological models of fission for some important neutron observables. Specific neutron correlations and their sensitivity to model inputs are then discussed.
Ramona Vogt is a staff physicist at Lawrence Livermore National Laboratory and an adjunct professor of physics at UC Davis. She obtained an AS degree from Kaskaskia College in 1983 and a BS in physics from the University of Illinois Urbana-Champaign in 1985. She received her PhD in nuclear physics from the State University of New York at Stony Brook in 1989. After postdoctoral positions in LLNL and GSI in Darmstadt, Germany she was a staff scientist at LBNL until she returned to take her staff appointment at LLNL in 2007. She became an adjunct professor of physics at UC Davis in 1995. She was named Fellow of the American Physical Society in 2010 and APS Outstanding Referee in 2016. She has been active in the APS, serving in various posts for the Executive Committee of the Topical Group on Hadronic Physics since 2008 and is currently a member of the DNP Program Committee.