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Title: Development of Platforms for Nuclear Science Experiments at the National Ignition Facility

Journal Article · · Stockpile Stewardship Quarterly
OSTI ID:1474390

When neutrons are produced in nuclear processes such as fission or fusion, they can interact with any surrounding materials, inducing radioactivity through neutron capture reactions. Neutron reactions are fundamental to many areas of nuclear science, including studies of nuclear reactors, determining the formation of matter in stars, nuclear forensics, medical radiotherapy, and assessing the safety of our nuclear stockpile. The National Ignition Facility (NIF) offers a unique opportunity to use the inertial confinement fusion platform to measure neutron reactions essential to national security or fundamental and applied science applications. A typical fusion experiment at NIF currently produces approximately 1016 neutrons through the fusion of deuterium and tritium in a target capsule. Materials introduced into the NIF target chamber in close proximity to the capsule will undergo neutron reactions such as capture or fission, and the resultant reaction rates can be evaluated. While neutron reactions can be measured at other facilities, NIF offers unique advantages. The flux of neutrons produced (number of neutrons per square centimeter per second) is much higher than any other available neutron source due to both the small size of the NIF capsule (2-mm diameter before implosion) and the short time (roughly 100 ps) over which the neutrons are produced. This results in less target material required to perform a reaction-rate study (less than or equal to 1016 atoms) as compared to traditional particle accelerators, which require targets that are approximately 1 mg or roughly 1020 atoms. Also, the NIF neutron spectrum is peaked at thermonuclear (14 MeV) neutron energy, which means that nuclear reactions with nonthermal energy thresholds can be studied at NIF, whereas neutron energies at a nuclear reactor are generally insufficient for studying higher-energy neutron reactions. Several experimental configurations have been developed that enable the use of NIF fusion capsules as powerful neutron sources for nuclear reaction measurements.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
AC52-07NA27344
OSTI ID:
1474390
Report Number(s):
LLNL-JRNL-749884; 935366
Journal Information:
Stockpile Stewardship Quarterly, Vol. 8; ISSN 9999-0016
Publisher:
USDOE NNSACopyright Statement
Country of Publication:
United States
Language:
English