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Title: Gamma Bang Time/Reaction History Diagnostics for the National Ignition Facility (NIF) Using 90-degree Off-axis Parabolic Mirrors

Abstract

Gas Cherenkov detectors (GCD) have been used to convert fusion gamma into photons to achieve gamma bang time (GBT) and reaction history measurements. The GCD designed for Omega used Cassegrain reflector optics in order to fit inside a ten-inch manipulator. A novel design for the National Ignition Facility (NIF) using 90º Off-Axis Parabolic (OAP) mirrors will increase light collection efficiency from fusion gammas and achieve minimum time dispersion. The broadband Cherenkov light (from 200 to 800 nm) is relayed into a high-speed detector using three parabolic mirrors. Because light is collected from many source planes throughout the CO2 gas volume, the detector is positioned at the stop position rather than an image position. The stop diameter and its position are independent of the light-generation location along the gas cell. The current design collects light from a 100-mm diameter by 500-mm-long gas volume. Optical ray tracings demonstrate how light can be collected from different angled trajectories of the Compton electrons as they fly through the CO2 gas volume. A cluster of four channels will allow for increased dynamic range as well as different gamma energy threshold sensitivities. 52.70.La, 29.40.Ka, 42.15.Eq, 07.60.-j, 07.85.-m

Authors:
Publication Date:
Research Org.:
National Security Technologies, LLC
Sponsoring Org.:
USDOE National Nuclear Security Administration (NA)
OSTI Identifier:
939694
Report Number(s):
DOE/NV/25946-471
TRN: US0900701
DOE Contract Number:  
DE-AC52-06NA25946
Resource Type:
Conference
Resource Relation:
Conference: 17th Topical Conference: High-Temperature Plasma Density; Albuquerque, NM; May 11-15, 2008
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; CHERENKOV COUNTERS; DESIGN; EFFICIENCY; ELECTRONS; MIRRORS; OPTICS; PHOTONS; PLASMA DENSITY; TRAJECTORIES; US NATIONAL IGNITION FACILITY; gamma bang time, National Ignition Facility, Optical Design

Citation Formats

H.W. Herrmann, R.M. Malone, W. Stoeffl, J.M. Mack, C.S. Young. Gamma Bang Time/Reaction History Diagnostics for the National Ignition Facility (NIF) Using 90-degree Off-axis Parabolic Mirrors. United States: N. p., 2008. Web.
H.W. Herrmann, R.M. Malone, W. Stoeffl, J.M. Mack, C.S. Young. Gamma Bang Time/Reaction History Diagnostics for the National Ignition Facility (NIF) Using 90-degree Off-axis Parabolic Mirrors. United States.
H.W. Herrmann, R.M. Malone, W. Stoeffl, J.M. Mack, C.S. Young. Sun . "Gamma Bang Time/Reaction History Diagnostics for the National Ignition Facility (NIF) Using 90-degree Off-axis Parabolic Mirrors". United States. https://www.osti.gov/servlets/purl/939694.
@article{osti_939694,
title = {Gamma Bang Time/Reaction History Diagnostics for the National Ignition Facility (NIF) Using 90-degree Off-axis Parabolic Mirrors},
author = {H.W. Herrmann, R.M. Malone, W. Stoeffl, J.M. Mack, C.S. Young},
abstractNote = {Gas Cherenkov detectors (GCD) have been used to convert fusion gamma into photons to achieve gamma bang time (GBT) and reaction history measurements. The GCD designed for Omega used Cassegrain reflector optics in order to fit inside a ten-inch manipulator. A novel design for the National Ignition Facility (NIF) using 90º Off-Axis Parabolic (OAP) mirrors will increase light collection efficiency from fusion gammas and achieve minimum time dispersion. The broadband Cherenkov light (from 200 to 800 nm) is relayed into a high-speed detector using three parabolic mirrors. Because light is collected from many source planes throughout the CO2 gas volume, the detector is positioned at the stop position rather than an image position. The stop diameter and its position are independent of the light-generation location along the gas cell. The current design collects light from a 100-mm diameter by 500-mm-long gas volume. Optical ray tracings demonstrate how light can be collected from different angled trajectories of the Compton electrons as they fly through the CO2 gas volume. A cluster of four channels will allow for increased dynamic range as well as different gamma energy threshold sensitivities. 52.70.La, 29.40.Ka, 42.15.Eq, 07.60.-j, 07.85.-m},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2008},
month = {6}
}

Conference:
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