Measurement of Laser-Plasma Electron Density with a Soft X-ray Laser Deflectometer

Ress, David; DaSilva, L.; London, R. A.; Trebes, J. E.; Mrowka, Stanley; Procassini, R.J.; Barbee, Troy W.; Lehr, D. E.

doi:10.1126/science.265.5171.514

Cited by 64 publications

(26 citation statements)

References 19 publications

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“…These experiments included shadowgraphy and radiography, 3 Moire deflectometry, 4 and interferometry 2,5 of dense large-scale plasmas. The studies provided insight into dense plasma phenomena unavailable through other techniques in spite of the low repetition rate ͑limited to several shots per day͒ and the high complexity of the laboratory x-ray laser probe.…”

Section: Dense Plasma Diagnostics With Table-top Soft X-ray Lasersmentioning

confidence: 99%

Application of extremely compact capillary discharge soft x-ray lasers to dense plasma diagnostics

et al. 2003

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Table-top capillary discharge soft x-ray lasers combine the advantages of a small size and a high repetition rate with an extremely high brightness similar to that of their laboratory-size predecessors. When utilized to probe high density plasmas their short wavelength results in a higher critical density, reduced refraction, decreased free-electron absorption, and higher resolution as compared to optical probes. These characteristics allow the design of experiments capable of measuring the evolution of plasmas with density-scale length products that are outside the reach of optical lasers. This paper reviews the use of a 46.9 nm wavelength Ne-like Ar capillary discharge table-top laser in dense plasma diagnostics, and reports soft x-ray laser interferometry results of spot-focus Nd:YAG laser plasmas created at moderate irradiation intensity (ϳ7ϫ10 12 W cm Ϫ2 ) with ϳ13 ns pulse width duration laser pulses. The measurements produced electron density maps with densities up to 0.9ϫ10 21 cm Ϫ3 that show the development of a concave electron density profile that differ significantly from those of a classical expansion. This two-dimensional behavior, that was recently also observed in line-focus plasmas, is analyzed here for the case of spot-focus plasmas with the assistance of hydrodynamic model simulations. The results demonstrate the use of a table-top soft x-ray laser interferometer as a new high resolution tool for the study of high density plasma phenomena and the validation of hydrodynamic codes.

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Section: Dense Plasma Diagnostics With Table-top Soft X-ray Lasersmentioning

confidence: 99%

Application of extremely compact capillary discharge soft x-ray lasers to dense plasma diagnostics

et al. 2003

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“…Similarly to equivalent approaches in the visible light 16,17 or soft X-ray range 18 , we recently showed that two gratings can be used for DPC imaging using polychromatic X-rays from brilliant synchrotron sources 19,20 . Here, we describe how the use of a third grating allows for a successful adaptation of the method to X-ray sources of low brilliance.…”

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confidence: 99%

Phase retrieval and differential phase-contrast imaging with low-brilliance X-ray sources

et al. 2006

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X -ray radiographic absorption imaging is an invaluable tool in medical diagnostics and materials science. For biological tissue samples, polymers or fibre composites, however, the use of conventional X-ray radiography is limited due to their weak absorption. This is resolved at highly brilliant X-ray synchrotron or micro-focus sources by using phase-sensitive imaging methods to improve the contrast 1,2 . However, the requirements of the illuminating radiation mean that hard-X-ray phase-sensitive imaging has until now been impractical with more readily available X-ray sources, such as X-ray tubes. In this letter, we report how a setup consisting of three transmission gratings can efficiently yield quantitative differential phase-contrast images with conventional X-ray tubes. In contrast with existing techniques, the method requires no spatial or temporal coherence, is mechanically robust, and can be scaled up to large fields of view. Our method provides all the benefits of contrast-enhanced phase-sensitive imaging, but is also fully compatible with conventional absorption radiography. It is applicable to X-ray medical imaging, industrial non-destructive testing, and to other low-brilliance radiation, such as neutrons or atoms.In conventional X-ray imaging, contrast is obtained through the differences in the absorption cross-section of the constituents of the object. The technique yields excellent results where highly absorbing structures such as bones are embedded in a matrix of relatively weakly absorbing material, for example the surrounding tissue of the human body. However, in cases where different forms of tissue with similar absorption cross-sections are under investigation (for example, mammography or angiography), the X-ray absorption contrast is relatively poor. Consequently, differentiating pathologic from non-pathologic tissue in an absorption radiograph obtained with a current hospital-based X-ray system remains practically impossible for certain tissue compositions.To overcome these limitations, several methods to generate radiographic contrast from the phase shift of X-rays passing through the sample have been investigated 3-13 . They can be classified into interferometric methods 3,4 , techniques using an analyser 5-7 and free-space propagation methods [8][9][10][11][12][13] . These methods differ vastly in the nature of the signal recorded, the experimental setup, and the requirements on the illuminating radiation. Because of the use of crystal optics, interferometric and analyser-based methods rely on a highly parallel and monochromatic X-ray beam. The required spatial and temporal coherence lengths 14 are given by ξ s = l( α/α) −1 and ξ t = l( E/E) −1 , where l is the wavelength, α/α is the angular acceptance and E/E is the energy band pass of the crystal optics. With typical values of α/α ≤ 10 −4 and E/E ≤ 10 −4 , they range in the order of ξ s ≥ 10 −6 m and ξ t ≥ 10 −6 m. Propagation-based methods can overcome the stringent requirements on the temporal coherence, and have been demonstrated to...

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“…For these reasons our initial measurements of electron density profiles in laser produced plasmas were obtained using Moiré deflectometry. 23 The technique is somewhat limiting, because it produces a signal proportional to the electron density gradient along only one dimension. However, its simplicity continues to have clear advantages; further demonstrations of this technique are reported in these proceedings.…”

Section: Electron Density Measurementmentioning

confidence: 99%

<title>Probing high-density plasmas with soft x-ray lasers</title>

Celliers

Barbee

Cauble

et al. 1997

Soft X-Ray Lasers and Applications II

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Measurement of Laser-Plasma Electron Density with a Soft X-ray Laser Deflectometer

Cited by 64 publications

References 19 publications

Application of extremely compact capillary discharge soft x-ray lasers to dense plasma diagnostics

Application of extremely compact capillary discharge soft x-ray lasers to dense plasma diagnostics

Phase retrieval and differential phase-contrast imaging with low-brilliance X-ray sources

<title>Probing high-density plasmas with soft x-ray lasers</title>

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