A dual high-energy radiography platform with 15 <i>μ</i>m resolution at the National Ignition Facility

Khan, S. F.; Martinez, D.; Kalantar, D. H.; Kirkwood, R. K.; Santos, C.; Ose, N.; Johnson, S.; Alessi, D.; Prantil, M.; Woods, D. T.; Glendinning, S. G.; Tommasini, R.; Mackinnon, A. J.; Prisbrey, Shon; Dittrich, Thomas; Bowers, M. W.; Cabral, J.B.; Crane, John K.; Nicola, J. M. Di; Hamamoto, M.; Herriot, S.; Lanier, T. E.; Lowe-Webb, R.; Pelz, L.; Widmayer, C.; Williams, Wade H.; Yang, S. T.

doi:10.1063/5.0044043

Cited by 4 publications

(1 citation statement)

References 15 publications

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“…LPP at the table-top scale are used as x-ray sources in commercial applications [15] and at the very large scale in inertial confinement fusion (ICF) research as very bright x-ray backlighters for capsule explosions. Petawattclass (PW) lasers facilities (such as ARC [16] and PETAL [17] or others mentioned at table E.1 in [18]) which can produce picosecond pulses of about kJ are used for these purposes. Even for ICF experiments, sources of soft x-rays are required.…”

Section: Introductionmentioning

confidence: 99%

Absolute keV x-ray yield and conversion efficiency in over dense Si sub-petawatt laser plasma

Ryazantsev¹,

Martynenko²,

Sedov³

et al. 2022

Plasma Phys. Control. Fusion

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Laser-produced plasmas are bright, short sources of X-rays commonly used for time-resolved imaging and spectroscopy. Their usage implies accurate knowledge of laser-to-X-ray conversion efficiency, spectrum, photon yield and angular distribution. Here we report on soft X-ray emission in the direction close to the target normal from a thin Si foil irradiated by a sub-PW picosecond laser pulse. These absolute measurements cover a continuous and broad spectral range that extends from 4.75 to 7.5 Å(1.7–2.6 keV). The X-ray spectrum consists of spectral line transitions from highly charged ions and broadband emission with contributions from recombination and free-free processes that occur when electrons decelerate in plasma electromagnetic fields. Angular distribution of the emission was investigated via PIC simulations, which allowed to estimate the yield into the full solid angle. We found that experiment and simulation estimations of laser to free-free emission conversion efficiency are in a good agreement.

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Section: Introductionmentioning

confidence: 99%

Absolute keV x-ray yield and conversion efficiency in over dense Si sub-petawatt laser plasma

Ryazantsev¹,

Martynenko²,

Sedov³

et al. 2022

Plasma Phys. Control. Fusion

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Characterization of a 1D-imaging high-energy x-ray backlighter driven by the National Ignition Facility Advanced Radiographic Capability laser

Hill

Williams

Kalantar

et al. 2022

Review of Scientific Instruments

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Plastic deformation of samples compressed to Mbar pressures at high strain rates at the National Ignition Facility (NIF) forms the basis of ongoing material strength experiments in conditions relevant to meteor impacts, geophysics, armor development, and inertial confinement fusion. Hard x-ray radiography is the primary means of measuring the evolution of these samples, typically employing a slit-collimated high-Z microdot driven by the NIF laser to generate [Formula: see text] keV x rays [E. Gumbrell et al., Rev. Sci. Instrum. 89, 10G118 (2018) and C. M. Huntington et al., Rev. Sci. Instrum. 89, 10G121 (2018)]. Alternatively, a dysprosium “micro-flag” target driven by the Advanced Radiographic Capability laser ([Formula: see text] kJ, 10 ps) can deliver significantly higher spatiotemporal resolution [M. P. Hill et al., Rev. Sci. Instrum. 92, 033535 (2021)], especially in high-opacity samples. Initial experiments revealed problematic brightness and spectral gradients from this source, but by radiographing a set of diamond-turned, 105 µm-thick Pb test objects and supported by simulations using the 3D Monte Carlo code GEANT4, these geometry-dependent gradients across the field of view are quantified and mitigation strategies are assessed. In addition to significantly enhancing the modulation transfer function compared to the existing system, image stacking from multiple layers of image plate is shown to almost double the signal to noise ratio that will reduce uncertainties in future dynamic strength experiments.

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Source size of x rays from self-modulated laser wakefield accelerators

Pagano,

Lemos,

King

et al. 2024

Physics of Plasmas

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A comparative study of x-ray sources generated with different mechanisms from self-modulated laser wakefield acceleration (SM-LWFA) electrons was performed to compare the source size or spatial resolution for use in high energy density science applications. We examine the source size of betatron, inverse Compton scattering, and bremsstrahlung radiation with a Fresnel diffraction based formalism and a modified x-ray ray tracing model. We observe the dependence of source size on the radiation generation process, laser parameters, and compare to what is possible in other regimes of LWFA, as well as current methods. This information is significant as we begin to explore the use of light sources driven by SM-LWFA for use as a diagnostic at large-scale laser facilities where blowout regime LWFA is not possible.

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A dual high-energy radiography platform with 15 μm resolution at the National Ignition Facility

Cited by 4 publications

References 15 publications

Absolute keV x-ray yield and conversion efficiency in over dense Si sub-petawatt laser plasma

Absolute keV x-ray yield and conversion efficiency in over dense Si sub-petawatt laser plasma

Characterization of a 1D-imaging high-energy x-ray backlighter driven by the National Ignition Facility Advanced Radiographic Capability laser

Source size of x rays from self-modulated laser wakefield accelerators

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