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Title: Hotspot electron temperature from x-ray continuum measurements on the NIF

We report on measurements of the electron temperature in the hotspot of inertially confined, layered, spherical implosions on the National Ignition Facility using a differential filtering diagnostic. Measurements of the DT and DD ion temperatures using neutron time-of-flight detectors are complicated by the contribution of hot spot motion to the peak width, which produce an apparent temperature higher than the thermal temperature. The electron temperature is not sensitive to this non-thermal velocity and is thus a valuable input to interpreting the stagnated hot spot conditions. Here we show that the current differential filtering diagnostic provides insufficient temperature resolution for the hot spot temperatures of interest. We then propose a new differential filter configuration utilizing larger pinhole size to increase spectral fluence, as well as thicker filtration. In conclusion, this new configuration will improve measurement uncertainty by more than a factor of three, allowing for a more accurate hotspot temperature.
Authors:
ORCiD logo [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ; ORCiD logo [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Report Number(s):
LLNL-CONF-698884
Journal ID: ISSN 0034-6748; RSINAK
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 87; Journal Issue: 11; Conference: Proceedings of the 21st Topical Conference on High-Temperature Plasma Diagnostics, Madison, WI (United States), 5-9 Jun 2016; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; 42 ENGINEERING
OSTI Identifier:
1289377