Talbot-Lau x-ray deflectometer: Refraction-based HEDP imaging diagnostic

Valdivia, M. P.; Stutman, D.; Stoeckl, C.; Theobald, W.; Collins, Gilbert; Bouffetier, V.; Vescovi, M.; Mileham, C.; Begishev, I. A.; Klein, Sallee; Melean, Raul; Muller, S.; Zou, Jun; Veloso, Felipe; Casner, Alexis; Beg, F. N.; Regan, S. P.

doi:10.1063/5.0043655

Cited by 5 publications

(6 citation statements)

References 31 publications

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“…Consequently, it is being intensively investigated for medical imaging of soft tissues [3][4][5], as well as non-destructive testing [6,7]. Currently the propagation-based approach [8] and the grating-based approach [9][10][11][12][13] are investigated for high energy density (HED) experiments.…”

Section: Introductionmentioning

confidence: 99%

Design of a Talbot phase-contrast microscopy imaging system with a digital detector for laser-driven X-ray backlighter sources

Schreiner,

Rauch,

Akstaller

et al. 2024

J. Inst.

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Laser-driven shock waves in matter propagate with multiple kilometers per second and therefore require sources like a laser-driven backlighter, which emit the X-rays within picoseconds, to be able to capture sharp images. The small spatial extent of shocks in low-density materials pose challenges on the imaging setup. In this work, we present a design process for a single-shot X-ray phase-contrast imaging system geared towards these objects, consisting of a two-grating Talbot interferometer and a digital X-ray detector. This imaging system is optimized with respect to the detectable refraction angle of the X-rays induced by an object, which implies a high phase sensitivity. Therefore, an optimization parameter is defined that considers experimental constraints such as the limited number of photons, the required magnification, the size and spectrum of the X-ray source, and the visibility of the moiré fringes. In this way, a large parameter space is sampled and a suitable imaging system is chosen. During a campaign at the PHELIX high-power laser facility a static test sample was imaged which is used to benchmark the optimization process and the imaging system under real conditions. The results show good agreement with the predicted performance, which demonstrates the reliability of the presented design process. Likewise, the process can be adapted to other types of laser experiments or X-ray sources and is not limited to the application presented here.

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Section: Introductionmentioning

confidence: 99%

Design of a Talbot phase-contrast microscopy imaging system with a digital detector for laser-driven X-ray backlighter sources

Schreiner,

Rauch,

Akstaller

et al. 2024

J. Inst.

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show abstract

“…Furthermore, a variation of the Talbot interferometer, called a Talbot-Lau interferometer, allows for non-coherent illumination by adding an additional micro-grating, thus creating an array of quasi-coherent sources [42,49,[56][57][58][59]. Therefore, TXD has been made available to diagnose HED plasma experiments using standard x-ray backlighters [21].…”

Section: Talbot-lau X-ray Interferometrymentioning

confidence: 99%

“…The location of the object being probed must be chosen considering that its location with respect to the gratings will determine system effective angular resolution [44,62] in addition to dictating object magnification which in turn impacts spatial resolution. Typically, if a laser-produced backlighter is used to illuminate the interferometer, a large Talbot magnification translates to better angular and spatial resolution [21]. Furthermore, although restrictions of maximum length should be considered, higher Talbot orders are preferred as they provide a narrower energy bandwidth (see figure 4, discussed later) [42].…”

Section: Talbot-lau X-ray Interferometrymentioning

confidence: 99%

“…In the case of the LCXP, this represents a total ∼8 keV photon count of ∼10 10 photons/ns/sr or greater. For comparison, laser-produced Cu K α sources (10 ps) have shown to produce ∼10 11−13 photons/pulse/sr [21].…”

Section: X-ray Backlighter Source Analysismentioning

confidence: 99%

“…Historically, a variety of x-ray backlighting imaging diagnostics have been employed in HED experiments, including high-resolution monochromatic x-ray imaging systems such as point-projection and pinhole cameras [3,[11][12][13][14], Kirkpatrick-Baez microscopes [15,16], Fresnel zone plates [17,18], and spherically bent crystal systems [19,20]. Typically, these diagnostics measure attenuation, however, when probing low-Z matter with ∼1-100 keV x-rays, the amount that the light is refracted is much more than the amount that is absorbed [21], as seen in figure 1 from [21]. Thus, a diagnostic utilizing refractive processes will deliver significantly higher contrast owing to higher phase-effects when compared to standard attenuation-based radiography.…”

Section: Introductionmentioning

confidence: 99%

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Wire, hybrid, and laser-cut X-pinches as Talbot–Lau backlighters for electron density diagnostics

Valdivia¹,

Collins²,

Conti³

et al. 2022

Plasma Phys. Control. Fusion

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Talbot-Lau X-ray Deflectometry (TXD) enables refraction-based imaging for high-energy-density physics (HEDP) experiments, and thus, it has been studied and developed with the goal of diagnosing plasmas relevant to Inertial Confinement and Magnetic Liner Inertial Fusion. X-pinches, known for reliably generating fast (~1 ns), small (~1 µm) x-ray sources, were driven on the compact current driver GenASIS (~200 kA, 150 ns) as a potential backlighter source for TXD. Considering that different X-pinch configurations have characteristic advantages and drawbacks as x-ray generating loads, three distinct copper X-pinch configurations were studied: the wire X-pinch, the hybrid X-pinch, and the laser-cut X-pinch. The Cu K-shell emission from each configuration was characterized and analyzed regarding the specific backlighter requirements for an 8 keV TXD system: spatial and temporal resolution, number of sources, time of emission, spectrum, and reproducibility. Recommendations for future experimental improvements and applications are presented. The electron density of static objects was retrieved from Moiré images obtained through TXD. This allowed to calculate the mass density of static samples within 4% of the expected value for laser-cut X-pinches, which were found to be the optimal X-pinch configuration for TXD due to their high reproducibility, small source size (≤5 µm), short duration (~1 ns FWHM), and up to 10^6 W peak power near 8 keV photon energy. Plasma loads were imaged through TXD for the first-time using laser-cut X-pinch backlighting. Experimental images were compared with simulations from the X-ray Wave-Front Propagation code, demonstrating that TXD can be a powerful x-ray refraction-based diagnostic for dense Z-pinch loads. Future plans for Talbot-Lau Interferometry diagnostics in the pulsed-power environment are described.

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Current advances on Talbot–Lau x-ray imaging diagnostics for high energy density experiments (invited)

Valdivia

Pérez-Callejo

Bouffetier

et al. 2022

Review of Scientific Instruments

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Talbot–Lau x-ray interferometry is a refraction-based diagnostic that can map electron density gradients through phase-contrast methods. The Talbot–Lau x-ray deflectometry (TXD) diagnostics have been deployed in several high energy density experiments. To improve diagnostic performance, a monochromatic TXD was implemented on the Multi-Tera Watt (MTW) laser using 8 keV multilayer mirrors (Δθ/θ = 4.5%-5.6%). Copper foil and wire targets were irradiated at 1014–1015 W/cm2. Laser pulse length (∼10 to 80 ps) and backlighter target configurations were explored in the context of Moiré fringe contrast and spatial resolution. Foil and wire targets delivered increased contrast <30%. The best spatial resolution (<6 μm) was measured for foils irradiated 80° from the surface. Further TXD diagnostic capability enhancement was achieved through the development of advanced data postprocessing tools. The Talbot Interferometry Analysis (TIA) code enabled x-ray refraction measurements from the MTW monochromatic TXD. Additionally, phase, attenuation, and dark-field maps of an ablating x-pinch load were retrieved through TXD. The images show a dense wire core of ∼60 μm diameter surrounded by low-density material of ∼40 μm thickness with an outer diameter ratio of ∼2.3. Attenuation at 8 keV was measured at ∼20% for the dense core and ∼10% for the low-density material. Instrumental and experimental limitations for monochromatic TXD diagnostics are presented. Enhanced postprocessing capabilities enabled by TIA are demonstrated in the context of high-intensity laser and pulsed power experimental data analysis. Significant advances in TXD diagnostic capabilities are presented. These results inform future diagnostic technique upgrades that will improve the accuracy of plasma characterization through TXD.

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Talbot-Lau x-ray deflectometer: Refraction-based HEDP imaging diagnostic

Cited by 5 publications

References 31 publications

Design of a Talbot phase-contrast microscopy imaging system with a digital detector for laser-driven X-ray backlighter sources

Design of a Talbot phase-contrast microscopy imaging system with a digital detector for laser-driven X-ray backlighter sources

Wire, hybrid, and laser-cut X-pinches as Talbot–Lau backlighters for electron density diagnostics

Current advances on Talbot–Lau x-ray imaging diagnostics for high energy density experiments (invited)

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