Talbot-Lau based Moiré deflectometry with non-coherent sources as potential High Energy Density plasma diagnostic

Journal Article · Fri Oct 25 04:00:00 EDT 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4827186· OSTI ID:1105007

Valdivia, M. P. ^[1]; Stutman, D. ^[2]; Finkenthal, M. ^[2]

---

1. Department of Physics and Astronomy, Johns Hopkins University , Baltimore, Maryland 21218, USA; Johns Hopkins University
2. Department of Physics and Astronomy, Johns Hopkins University , Baltimore, Maryland 21218, USA

X-ray phase-contrast radiography could better characterize highly localized density gradients expected in High Energy Density (HED) plasma experiments than conventional attenuation radiography. In particular, the Talbot-Lau (TL) grating interferometer, which works with extended and polychromatic x-ray sources, is a potentially attractive HED diagnostic due to its high sensitivity. For HED characterization the TL setup and imaging techniques must be changed from the recently studied medical system. The object magnification must be increased greatly in order to resolve μm scale gradients while the Talbot magnification must be increased in order to keep the gratings away from the plasma. Additionally, techniques for retrieving the density profile from a single plasma image must be developed. We thus study the performance of high magnification TL interferometers, in conjunction with Moiré fringe deflectometry for single image phase retrieval. The results show a very good interferometer contrast (≤30%) at high magnification. The Moiré technique enables measuring both sharp and mild density gradients with good accuracy and spatial resolution. Both the laboratory and simulation studies indicate that the TL based Moiré deflectometry is more sensitive than the propagation phase-contrast method when utilizing an extended x-ray source (~80μm). In HED experiments this would allow for less demanding X-ray backlighters than those used at present.

• Research Organization: Johns Hopkins Univ., Baltimore, MD (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: NA0001835
• OSTI ID: 1105007
• Report Number(s): DOE/NA0001835-2
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 16 Vol. 114; ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English