The low natural background rates and the penetrating nature of neutron radiation makes neutron detection a good method for quantifying and accounting for large amounts of special nuclear material capable of neutron induced fission and fission chains. Almost from the beginning of the atomic age, the measurement of time-correlated neutrons has been used to detect and quantify fission and fission processes. Richard Feynman himself proposed a method, the grandfather of what is used today, to compare correlation rates of neutron flux in a fixed time window, to that which would be expected from a random neutron source, in order to prove that fission was taking place in early reactor experiments. Fission is one of the few natural processes that produces time-correlated neutrons, the others are spallation-type processes (e.g. (n,xn), cosmic induced background, etc). We will discuss the use of such methods in detection, material accountability, arms control verification and the assessment of unknown objects for nuclear material, topics of particular interest in the world today.
Leslie F. Nakae
Current Position:
Staff Physicist, Nuclear and Chemical Sciences Division
Lawrence Livermore National Laboratory
Education:
Ph.D. Brandeis University, Waltham, MA (Elementary Particle Physics, January 1992)
M.S. Stanford University, Stanford, CA (Geophysics, June 1985)
M.S. University of Michigan, Ann Arbor, MI (Physics, Dec 1981)
A.B. University of California, Berkeley, CA (Physics and Applied Math, June 1980
Currently PI for numerous projects supporting various programs related to the radiation detection and assessment of Special Nuclear Materials. These programs involve arms control treaty verification and safeguards monitoring as well as nuclear threat assessment. Current projects include development of Detection and Analysis systems employing fast time correlated and spectral analysis of neutrons and gamma rays for Non-Proliferation Verification, Nuclear Safeguards and Nuclear Threat Assessment.
On staff at LLNL from 1994-present, Previous Positions: Computer Systems Analyst, Post Doctoral Researcher (SSC Lab), Radar Systems Analyst, Graduate Student Assistant (LBNL, FNAL).