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Title: Uncertainty analysis of response functions and γ-backgrounds on Tion and t0 measurements from Cherenkov neutron detectors at the National Ignition Facility (NIF)

Abstract

Cherenkov radiators deployed to measure the neutron time-of-flight spectrum have response times associated with the neutron transit across the detector and are free from long time response tails characteristic of scintillation detectors. The Cherenkov radiation results from simple physical processes which makes them amenable to high fidelity Monte Carlo simulation. The instrument response function of neutron time-of-flight systems is a major contributor to both the systematic and statistical uncertainties of the parameters used to describe these spectra; in particular, the first and second moments of these distributions are associated with arrival time, t0, and ion temperature, Tion. We introduce the results of uncertainty analysis showing the crucial reduction of the uncertainty in determining these quantities in the Cherenkov detector system recently deployed at NIF. The increased sensitivity to gamma radiation requires additional consideration of the effect of this background to the uncertainties in both t0 and Tion.

Authors:
ORCiD logo [1];  [1];  [1];  [1];  [1];  [1];  [2];  [1]; ORCiD logo [1];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Atomic Weapons Establishment (AWE), Berkshire (United Kingdom)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC); U.K. Ministry of Defence
OSTI Identifier:
1545505
Alternate Identifier(s):
OSTI ID: 1477909
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 89; Journal Issue: 10; Conference: 22. Proceedings of the Topical Conference on High-Temperature Plasma Diagnostics, San Diego, CA (United States), Apr 2018; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY

Citation Formats

Hartouni, E. P., Beeman, B., Eckart, M. J., Grim, G. P., Hatarik, R., Moore, A. S., Rubery, M., Sayre, D., Schlossberg, D. J., and Waltz, C. Uncertainty analysis of response functions and γ-backgrounds on Tion and t0 measurements from Cherenkov neutron detectors at the National Ignition Facility (NIF). United States: N. p., 2018. Web. doi:10.1063/1.5038816.
Hartouni, E. P., Beeman, B., Eckart, M. J., Grim, G. P., Hatarik, R., Moore, A. S., Rubery, M., Sayre, D., Schlossberg, D. J., & Waltz, C. Uncertainty analysis of response functions and γ-backgrounds on Tion and t0 measurements from Cherenkov neutron detectors at the National Ignition Facility (NIF). United States. doi:10.1063/1.5038816.
Hartouni, E. P., Beeman, B., Eckart, M. J., Grim, G. P., Hatarik, R., Moore, A. S., Rubery, M., Sayre, D., Schlossberg, D. J., and Waltz, C. Wed . "Uncertainty analysis of response functions and γ-backgrounds on Tion and t0 measurements from Cherenkov neutron detectors at the National Ignition Facility (NIF)". United States. doi:10.1063/1.5038816. https://www.osti.gov/servlets/purl/1545505.
@article{osti_1545505,
title = {Uncertainty analysis of response functions and γ-backgrounds on Tion and t0 measurements from Cherenkov neutron detectors at the National Ignition Facility (NIF)},
author = {Hartouni, E. P. and Beeman, B. and Eckart, M. J. and Grim, G. P. and Hatarik, R. and Moore, A. S. and Rubery, M. and Sayre, D. and Schlossberg, D. J. and Waltz, C.},
abstractNote = {Cherenkov radiators deployed to measure the neutron time-of-flight spectrum have response times associated with the neutron transit across the detector and are free from long time response tails characteristic of scintillation detectors. The Cherenkov radiation results from simple physical processes which makes them amenable to high fidelity Monte Carlo simulation. The instrument response function of neutron time-of-flight systems is a major contributor to both the systematic and statistical uncertainties of the parameters used to describe these spectra; in particular, the first and second moments of these distributions are associated with arrival time, t0, and ion temperature, Tion. We introduce the results of uncertainty analysis showing the crucial reduction of the uncertainty in determining these quantities in the Cherenkov detector system recently deployed at NIF. The increased sensitivity to gamma radiation requires additional consideration of the effect of this background to the uncertainties in both t0 and Tion.},
doi = {10.1063/1.5038816},
journal = {Review of Scientific Instruments},
number = 10,
volume = 89,
place = {United States},
year = {2018},
month = {10}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Figures / Tables:

FIG. 1 FIG. 1: Typical neutron time-of-flight spectrum from a 5 keV DT plasma (in gray). The inset shows the fused silica IRF for the detection system used in this analysis.

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    journal, October 2018

    • Schlossberg, D. J.; Moore, A. S.; Beeman, B. V.
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