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Title: Study of Scattered Background Neutron in NIF and Time-of Flight (TOF) to Measure Neutron

Abstract

Some of the planned core diagnostics for National Ignition Facility (NIF) will use neutron time-of-flight (TOF) spectroscopy techniques to gather information for primary neutron yield measurement or neutron imaging. This technique has been widely and routinely used at other laser facilities including Nova and Omega. TOF methods will also be used to observe target fuel areal density <{rho}R> (radial integral of density) via measuring the number of primary 14.1 MeV neutrons that are down-scattered to lower energies by nuclear collisions inside the compressed target core. The substantially larger target chamber size and higher neutron yield for NIF raises issues related to the large number of scattered neutrons produced by high yield deuterium-tritium (D-T) shots at NIF. The effect of primary neutrons scattered by the walls of the massive target chamber and structures both inside and outside the chamber will contribute a significant scattered background signal when trying to determine the number of neutrons down-scattered from the target core. The optimum detector locations outside the target chamber or target bay wall will be proposed. Appropriate collimators at the chamber port and the bay wall (between the neutron source at target chamber center (TCC) and detector) that maximize detection of signal neutronsmore » while minimizing the background from scattered neutrons and neutron induced gamma rays will also be presented.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
883559
Report Number(s):
UCRL-CONF-215021
Journal ID: ISSN 1155--4339; TRN: US200615%%129
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Journal Volume: 133; Conference: Presented at: 2005 Fourth International Conference on Inertial Fusion Sciences and Applications, Biarritz, France, Sep 04 - Sep 09, 2005
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COLLIMATORS; DETECTION; LASERS; NEUTRON SOURCES; NEUTRONS; SPECTROSCOPY; TARGET CHAMBERS; TARGETS; US NATIONAL IGNITION FACILITY

Citation Formats

Song, P, Moran, M, Phillips, T, Lerche, R, Koch, J, and Eder, D. Study of Scattered Background Neutron in NIF and Time-of Flight (TOF) to Measure Neutron. United States: N. p., 2005. Web. doi:10.1051/jp4:2006133187.
Song, P, Moran, M, Phillips, T, Lerche, R, Koch, J, & Eder, D. Study of Scattered Background Neutron in NIF and Time-of Flight (TOF) to Measure Neutron. United States. https://doi.org/10.1051/jp4:2006133187
Song, P, Moran, M, Phillips, T, Lerche, R, Koch, J, and Eder, D. Wed . "Study of Scattered Background Neutron in NIF and Time-of Flight (TOF) to Measure Neutron". United States. https://doi.org/10.1051/jp4:2006133187. https://www.osti.gov/servlets/purl/883559.
@article{osti_883559,
title = {Study of Scattered Background Neutron in NIF and Time-of Flight (TOF) to Measure Neutron},
author = {Song, P and Moran, M and Phillips, T and Lerche, R and Koch, J and Eder, D},
abstractNote = {Some of the planned core diagnostics for National Ignition Facility (NIF) will use neutron time-of-flight (TOF) spectroscopy techniques to gather information for primary neutron yield measurement or neutron imaging. This technique has been widely and routinely used at other laser facilities including Nova and Omega. TOF methods will also be used to observe target fuel areal density <{rho}R> (radial integral of density) via measuring the number of primary 14.1 MeV neutrons that are down-scattered to lower energies by nuclear collisions inside the compressed target core. The substantially larger target chamber size and higher neutron yield for NIF raises issues related to the large number of scattered neutrons produced by high yield deuterium-tritium (D-T) shots at NIF. The effect of primary neutrons scattered by the walls of the massive target chamber and structures both inside and outside the chamber will contribute a significant scattered background signal when trying to determine the number of neutrons down-scattered from the target core. The optimum detector locations outside the target chamber or target bay wall will be proposed. Appropriate collimators at the chamber port and the bay wall (between the neutron source at target chamber center (TCC) and detector) that maximize detection of signal neutrons while minimizing the background from scattered neutrons and neutron induced gamma rays will also be presented.},
doi = {10.1051/jp4:2006133187},
url = {https://www.osti.gov/biblio/883559}, journal = {},
issn = {1155--4339},
number = ,
volume = 133,
place = {United States},
year = {2005},
month = {8}
}

Conference:
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