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Title: Modeling the National Ignition Facility neutron imaging system

Abstract

Numerical modeling of the neutron imaging system for the National Ignition Facility (NIF), forward from calculated target neutron emission to a camera image, will guide both the reduction of data and the future development of the system. Located 28 m from target chamber center, the system can produce two images at different neutron energies by gating on neutron arrival time. The brighter image, using neutrons near 14 MeV, reflects the size and symmetry of the implosion ''hot spot.'' A second image in scattered neutrons, 10-12 MeV, reflects the size and symmetry of colder, denser fuel, but with only {approx}1%-7% of the neutrons. A misalignment of the pinhole assembly up to {+-}175 {mu}m is covered by a set of 37 subapertures with different pointings. The model includes the variability of the pinhole point spread function across the field of view. Omega experiments provided absolute calibration, scintillator spatial broadening, and the level of residual light in the down-scattered image from the primary neutrons. Application of the model to light decay measurements of EJ399, BC422, BCF99-55, Xylene, DPAC-30, and Liquid A suggests that DPAC-30 and Liquid A would be preferred over the BCF99-55 scintillator chosen for the first NIF system, if they couldmore » be fabricated into detectors with sufficient resolution.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1]; ; ; ; ;  [2] more »; « less
  1. Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)
  2. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
Publication Date:
OSTI Identifier:
22055773
Resource Type:
Journal Article
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 81; Journal Issue: 10; Other Information: (c) 2010 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0034-6748
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CALIBRATION; CAMERAS; HOT SPOTS; IMAGES; IMPLOSIONS; LIQUIDS; MEV RANGE; NEUTRON DETECTION; NEUTRON EMISSION; NEUTRONS; PLASMA; RESOLUTION; SCINTILLATION COUNTERS; SIMULATION; TARGET CHAMBERS; US NATIONAL IGNITION FACILITY; VISIBLE RADIATION; XYLENES

Citation Formats

Wilson, D C, Grim, G P, Tregillis, I L, Wilke, M D, Morgan, G L, Loomis, E N, Wilde, C H, Oertel, J A, Fatherley, V E, Clark, D D, Schmitt, M J, Merrill, F E, Wang, T.-S. F., Danly, C R, Batha, S H, Patel, M V, Sepke, S M, Hatarik, R, Fittinghoff, D N, Bower, D E, and others, and. Modeling the National Ignition Facility neutron imaging system. United States: N. p., 2010. Web. doi:10.1063/1.3496993.
Wilson, D C, Grim, G P, Tregillis, I L, Wilke, M D, Morgan, G L, Loomis, E N, Wilde, C H, Oertel, J A, Fatherley, V E, Clark, D D, Schmitt, M J, Merrill, F E, Wang, T.-S. F., Danly, C R, Batha, S H, Patel, M V, Sepke, S M, Hatarik, R, Fittinghoff, D N, Bower, D E, & others, and. Modeling the National Ignition Facility neutron imaging system. United States. https://doi.org/10.1063/1.3496993
Wilson, D C, Grim, G P, Tregillis, I L, Wilke, M D, Morgan, G L, Loomis, E N, Wilde, C H, Oertel, J A, Fatherley, V E, Clark, D D, Schmitt, M J, Merrill, F E, Wang, T.-S. F., Danly, C R, Batha, S H, Patel, M V, Sepke, S M, Hatarik, R, Fittinghoff, D N, Bower, D E, and others, and. 2010. "Modeling the National Ignition Facility neutron imaging system". United States. https://doi.org/10.1063/1.3496993.
@article{osti_22055773,
title = {Modeling the National Ignition Facility neutron imaging system},
author = {Wilson, D C and Grim, G P and Tregillis, I L and Wilke, M D and Morgan, G L and Loomis, E N and Wilde, C H and Oertel, J A and Fatherley, V E and Clark, D D and Schmitt, M J and Merrill, F E and Wang, T.-S. F. and Danly, C R and Batha, S H and Patel, M V and Sepke, S M and Hatarik, R and Fittinghoff, D N and Bower, D E and others, and},
abstractNote = {Numerical modeling of the neutron imaging system for the National Ignition Facility (NIF), forward from calculated target neutron emission to a camera image, will guide both the reduction of data and the future development of the system. Located 28 m from target chamber center, the system can produce two images at different neutron energies by gating on neutron arrival time. The brighter image, using neutrons near 14 MeV, reflects the size and symmetry of the implosion ''hot spot.'' A second image in scattered neutrons, 10-12 MeV, reflects the size and symmetry of colder, denser fuel, but with only {approx}1%-7% of the neutrons. A misalignment of the pinhole assembly up to {+-}175 {mu}m is covered by a set of 37 subapertures with different pointings. The model includes the variability of the pinhole point spread function across the field of view. Omega experiments provided absolute calibration, scintillator spatial broadening, and the level of residual light in the down-scattered image from the primary neutrons. Application of the model to light decay measurements of EJ399, BC422, BCF99-55, Xylene, DPAC-30, and Liquid A suggests that DPAC-30 and Liquid A would be preferred over the BCF99-55 scintillator chosen for the first NIF system, if they could be fabricated into detectors with sufficient resolution.},
doi = {10.1063/1.3496993},
url = {https://www.osti.gov/biblio/22055773}, journal = {Review of Scientific Instruments},
issn = {0034-6748},
number = 10,
volume = 81,
place = {United States},
year = {2010},
month = {10}
}