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Title: Implementing time resolved electron temperature capability at the NIF using a streak camera

Abstract

A new capability on NIF has been implemented to measure the temperature of x-ray emitting sources. Although it is designed primarily for Inertial Confinement Fusion (ICF), it can be used for any hot emitting source that is well modeled. The electron temperature (T e) of the hot spot within the core of imploded inertial confinement fusion capsules is an effective indicator of implosion performance. Currently, there are spatially and temporally integrated T e inferences using image plates. A temporally resolved measurement of Te will help elucidate the mechanisms for hot spot heating and cooling such as conduction to fuel, alpha-heating, mix and radiative losses. To determine the temporally resolved T e of hot spots, specific filters are added to an existing x-ray streak camera “Streaked Polar Instrumentation for Diagnosing Energetic Radiation (SPIDER)” to probe the emission spectrum during the x-ray burn history of implosions on the National Ignition Facility (NIF). One of the difficulties in inferring the hot spot temperature is the attenuation of the emission due to opacity from the shell and fuel. Therefore, a series of increasingly thick titanium filters were implemented to isolate the emission in specific energy regions that are sensitive to temperatures above 3keV whilemore » not significantly influenced by the shell/fuel attenuation. Additionally, a relatively thin zinc filter was used to measure the contribution of colder emission sources. Since the signal levels of the emission through the thicker filters are relatively poor, a dual slit (aperture) was designed to increase detected signal at the higher end of the spectrum. Herein, the design of the filters and slit are described, an overview of the solving technique is provided, and initial electron temperature results are reported.« less

Authors:
 [1]; ORCiD logo [1];  [1]; ORCiD logo [1];  [1]; ORCiD logo [1];  [1]; ORCiD logo [1];  [2];  [3];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Nevada National Security Site, Livermore, CA (United States)
  3. General Atomics, San Diego, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1497302
Alternate Identifier(s):
OSTI ID: 1478440
Report Number(s):
LLNL-JRNL-750877
Journal ID: ISSN 0034-6748; 936400
Grant/Contract Number:  
AC52-07NA27344; DEAC52- 07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 89; Journal Issue: 10; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION

Citation Formats

Khan, S. F., Jarrott, L. C., Patel, P. K., Izumi, N., Ma, T., MacPhee, A. G., Hatch, B., Landen, O. L., Heinmiller, J., Kilkenny, J. D., and Bradley, D. K. Implementing time resolved electron temperature capability at the NIF using a streak camera. United States: N. p., 2018. Web. doi:10.1063/1.5039382.
Khan, S. F., Jarrott, L. C., Patel, P. K., Izumi, N., Ma, T., MacPhee, A. G., Hatch, B., Landen, O. L., Heinmiller, J., Kilkenny, J. D., & Bradley, D. K. Implementing time resolved electron temperature capability at the NIF using a streak camera. United States. doi:10.1063/1.5039382.
Khan, S. F., Jarrott, L. C., Patel, P. K., Izumi, N., Ma, T., MacPhee, A. G., Hatch, B., Landen, O. L., Heinmiller, J., Kilkenny, J. D., and Bradley, D. K. Mon . "Implementing time resolved electron temperature capability at the NIF using a streak camera". United States. doi:10.1063/1.5039382.
@article{osti_1497302,
title = {Implementing time resolved electron temperature capability at the NIF using a streak camera},
author = {Khan, S. F. and Jarrott, L. C. and Patel, P. K. and Izumi, N. and Ma, T. and MacPhee, A. G. and Hatch, B. and Landen, O. L. and Heinmiller, J. and Kilkenny, J. D. and Bradley, D. K.},
abstractNote = {A new capability on NIF has been implemented to measure the temperature of x-ray emitting sources. Although it is designed primarily for Inertial Confinement Fusion (ICF), it can be used for any hot emitting source that is well modeled. The electron temperature (Te) of the hot spot within the core of imploded inertial confinement fusion capsules is an effective indicator of implosion performance. Currently, there are spatially and temporally integrated Te inferences using image plates. A temporally resolved measurement of Te will help elucidate the mechanisms for hot spot heating and cooling such as conduction to fuel, alpha-heating, mix and radiative losses. To determine the temporally resolved Te of hot spots, specific filters are added to an existing x-ray streak camera “Streaked Polar Instrumentation for Diagnosing Energetic Radiation (SPIDER)” to probe the emission spectrum during the x-ray burn history of implosions on the National Ignition Facility (NIF). One of the difficulties in inferring the hot spot temperature is the attenuation of the emission due to opacity from the shell and fuel. Therefore, a series of increasingly thick titanium filters were implemented to isolate the emission in specific energy regions that are sensitive to temperatures above 3keV while not significantly influenced by the shell/fuel attenuation. Additionally, a relatively thin zinc filter was used to measure the contribution of colder emission sources. Since the signal levels of the emission through the thicker filters are relatively poor, a dual slit (aperture) was designed to increase detected signal at the higher end of the spectrum. Herein, the design of the filters and slit are described, an overview of the solving technique is provided, and initial electron temperature results are reported.},
doi = {10.1063/1.5039382},
journal = {Review of Scientific Instruments},
issn = {0034-6748},
number = 10,
volume = 89,
place = {United States},
year = {2018},
month = {10}
}

Journal Article:
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This content will become publicly available on October 22, 2019
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