Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic
An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Labs (LLNL). This diagnostic is designed to make measurements of hohlraum plasma parameters, such as the electron temperature and density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature hohlraums produce intense soft x-ray emission, which can cause “blanking” (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ~ 8 J cm-2. This is then significantly above the expected threshold for the onset of “blanking” effects. A novel Xenon Plasma X-ray Shield (XPXS) has been proposed to protect the blast shield from x-rays and mitigate “blanking”. Finally, these estimates suggest that an areal density of 1019 cm-2 Xe atoms will be sufficient to absorb 99.5% the soft x-ray flux. Two potential designs for this shield are presented.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC52-07NA27344
- OSTI ID:
- 1258507
- Report Number(s):
- LLNL-CONF-693137; RSINAK
- Journal Information:
- Review of Scientific Instruments, Vol. 87, Issue 11; Conference: Presented at: High Temperature Plasma Diagnostics, Madiso, WI, United States, Jun 05 - Jun 09, 2016; ISSN 0034-6748
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Impact of non-Maxwellian electron velocity distribution functions on inferred plasma parameters in collective Thomson scattering
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journal | February 2019 |
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