1. Measuring neutron yield and ρR anisotropies with activation foils at the National Ignition Facility.
- Author
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Bleuel, D. L., Bernstein, L. A., Bionta, R. M., Cooper, G. W., Drury, O. B., Hagmann, C. A., Knittel, K. M., Leeper, R. J., Ruiz, C. L., Schneider, D. H. G., and Yeamans, C. B.
- Subjects
NEUTRONS ,INDIUM ,GAMMA rays ,ZIRCONIUM ,ANISOTROPY - Abstract
Neutron yields at the National Ignition Facility (NIF) are measured with a suite of diagnostics, including activation of ~20-200 g samples of materials undergoing a variety of energy-dependent neutron reactions. Indium samples were mounted on the end of a Diagnostic Instrument Manipulator (DIM), 25-50 cm from the implosion, to measure 2.45MeV D-D fusion neutron yield. The 336.2 keV gamma rays from the 4.5 hour isomer of 115mIn produced by (n,2n) reactions are counted in high-purity germanium detectors. For capsules producing D-T fusion reactions, zirconium and copper are activated via (n,2n) reactions at various locations around the target chamber and bay, measuring the 14MeV neutron yield to accuracies on order of 7%. By mounting zirconium samples on ports at nine locations around the NIF chamber, anisotropies in the primary neutron emission due to fuel areal density asymmetries can be measured to a relative precision of 3%. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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