Development of an x-ray Talbot-Lau moiré deflectometer for fast density profile measurements of dense plasmas generated by beam-target interactions

Journal Article · Thu Oct 15 00:00:00 EDT 2015 · IEEE Pulsed Power Conference

DOI:https://doi.org/10.1109/PPC.2015.7297002· OSTI ID:1258587

Clayton, D. J. ^[1]; Berninger, M. ^[1]; Meidinger, A. ^[1]; Stutman, D. ^[2]; Valdivia, M. P. ^[2]

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1. National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States)
2. Johns Hopkins Univ., Baltimore, MD (United States)

We report that for the first time an x-ray Talbot-Lau moiré deflectometer is being developed that will use a flash tube source and fast detector for dynamic density gradient measurements. In Talbot-Lau moiré deflectometry, an x-ray grating makes an image of itself on a second grating (the Talbot effect) to produce a moiré pattern on a detector. The test object is placed between these gratings, with variations in index of refraction changing the pattern. A third grating in front of an incoherent x-ray source produces an array of coherent sources. With a 150 kV x-ray flash tube as the source, the gratings are placed in a glancing angle setup for performance at ~60 keV. The detector is a gated CCD with a fast scintillator for x-ray conversion. This diagnostic, designed for the Dual-Axis Radiographic Hydrodynamic Test facility (DARHT) at Los Alamos National Laboratory, measures the density profile of dense plasma plumes ejected from beam-target interactions. DARHT has two high-current, pulsed, inductive linear electron accelerators with bremsstrahlung targets at the end of each beam line to create 2-D radiographic images of hydrodynamic tests. One multi-pulse accelerator has up to four beam pulses striking the same target within 2 μs. Computer simulations that model target evolution and ejected material between pulses are used to design these targets for optimal radiographic performance; the x-ray deflectometer will directly measure density gradients in the ejected plumes and provide the first experimental constraints to these models. During the first year, currently underway, the diagnostic systems are being designed. In year two, the flash tube and fast detector will be deployed at DARHT for radiographic imaging while the deflectometer is built and tested on the bench with a continuous source. In year three, the fast deflectometer will be installed on DARHT and density measurements will be performed.

• Research Organization: Johns Hopkins Univ., Baltimore, MD (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: NA0002955
• OSTI ID: 1258587
• Journal Information: IEEE Pulsed Power Conference, Vol. 2015; Conference: 20.IEEE Pulsed Power Conference (PPC), Austin, TX (United States), 31 May - 4 Jun 2015; Related Information: 2015 IEEE Pulsed Power Conference (PPC), ISBN 978-1-4799-8403-9; ISSN 2158-4915
• Publisher: IEEE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
plasma density
plasma diagnostics
plasma sources