Preliminary Measurements of X-Ray and Neutron Emission from Laser-Produced Plasmas

Mead, S.W.; Kidder, Ray E.; Swain, J.E.; Ranier, F.; Petruzzi, J.

doi:10.1364/ao.11.000345

Cited by 51 publications

(11 citation statements)

References 12 publications

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“…Further improvements in sensitivity (by about a factor of 5) may be obtained by utilizing pyrolytic graphite as the diffracting crystal (see Table 2). It is also possible to deposit pyrolytic graphite onto a cylindrical substrate and thus circumvent the problems of bending crystals to cylindrical shapes (Mead et al 1972).…”

Section: (B) Efficiency 0/ X-ray Production and Detectionmentioning

confidence: 99%

EXAFS Spectroscopy by Continuum Soft X-ray Emission from a Short Pulse Laser-produced Plasma

Tallents¹,

Luther‐Davies²,

Horsburgh³

1986

Aust. J. Phys.

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The use of a laser-produced plasma created by low ener~y (E :::;; 61), ps duration laser pulses as the X-ray source for EXAFS spectroscopy in the 3-8 A wavelength band is investigated. We consider the various factors that affect the X-ray flux at the detector plane and investigate ways of optimizing that flux. A simple qualitative model has been used to describe the way in which the source intensity scales with parameters·such as the laser intensity. Practical problems associated with the implementation of the various different X-ray dispersive elements and detectors are discussed.

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Section: (B) Efficiency 0/ X-ray Production and Detectionmentioning

confidence: 99%

EXAFS Spectroscopy by Continuum Soft X-ray Emission from a Short Pulse Laser-produced Plasma

Tallents¹,

Luther‐Davies²,

Horsburgh³

1986

Aust. J. Phys.

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“…Focal spot size was determined by methods previously described. 105 The 20-psec structure and 1.2-A spectrum peri odicities observed in Figs. 88 and °0a, respectively, originate in the oscillator from a 3-mm-fhjck window in a Pockets cell used for Q.-switching.…”

Section: Recent Results With the Long Path Lasermentioning

confidence: 93%

Laser-Fusion Program Semiannual Report: January--June 1972.

Kachen¹,

Clements²,

Genin³

1972

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“…In 1972, Mead et al 71 ) and found on the basis of time-of-flight measurements that the neutrons came from the target. However, based on their hydrodynamic predictions of just 10 -2 neutrons per shot and observations that the neutrons disappeared when a background gas was added, they concluded that the neutrons were not thermonuclear.…”

Section: A the Quest For Neutronsmentioning

confidence: 99%

Direct-drive inertial confinement fusion: A review

et al. 2015

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The direct-drive, laser-based approach to inertial confinement fusion (ICF) is reviewed from its inception following the demonstration of the first laser to its implementation on the present generation of high-power lasers. The review focuses on the evolution of scientific understanding gained from target-physics experiments in many areas, identifying problems that were demonstrated and the solutions implemented. The review starts with the basic understanding of laser–plasma interactions that was obtained before the declassification of laser-induced compression in the early 1970s and continues with the compression experiments using infrared lasers in the late 1970s that produced thermonuclear neutrons. The problem of suprathermal electrons and the target preheat that they caused, associated with the infrared laser wavelength, led to lasers being built after 1980 to operate at shorter wavelengths, especially 0.35 μm—the third harmonic of the Nd:glass laser—and 0.248 μm (the KrF gas laser). The main physics areas relevant to direct drive are reviewed. The primary absorption mechanism at short wavelengths is classical inverse bremsstrahlung. Nonuniformities imprinted on the target by laser irradiation have been addressed by the development of a number of beam-smoothing techniques and imprint-mitigation strategies. The effects of hydrodynamic instabilities are mitigated by a combination of imprint reduction and target designs that minimize the instability growth rates. Several coronal plasma physics processes are reviewed. The two-plasmon–decay instability, stimulated Brillouin scattering (together with cross-beam energy transfer), and (possibly) stimulated Raman scattering are identified as potential concerns, placing constraints on the laser intensities used in target designs, while other processes (self-focusing and filamentation, the parametric decay instability, and magnetic fields), once considered important, are now of lesser concern for mainline direct-drive target concepts. Filamentation is largely suppressed by beam smoothing. Thermal transport modeling, important to the interpretation of experiments and to target design, has been found to be nonlocal in nature. Advances in shock timing and equation-of-state measurements relevant to direct-drive ICF are reported. Room-temperature implosions have provided an increased understanding of the importance of stability and uniformity. The evolution of cryogenic implosion capabilities, leading to an extensive series carried out on the 60-beam OMEGA laser [Boehly et al., Opt. Commun. 133, 495 (1997)], is reviewed together with major advances in cryogenic target formation. A polar-drive concept has been developed that will enable direct-drive–ignition experiments to be performed on the National Ignition Facility [Haynam et al., Appl. Opt. 46(16), 3276 (2007)]. The advantages offered by the alternative approaches of fast ignition and shock ignition and the issues associated with these concepts are described. The lessons learned from target-physics and implosion experiments are taken into account in ignition and high-gain target designs for laser wavelengths of 1/3 μm and 1/4 μm. Substantial advances in direct-drive inertial fusion reactor concepts are reviewed. Overall, the progress in scientific understanding over the past five decades has been enormous, to the point that inertial fusion energy using direct drive shows significant promise as a future environmentally attractive energy source.

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Preliminary Measurements of X-Ray and Neutron Emission from Laser-Produced Plasmas

Cited by 51 publications

References 12 publications

EXAFS Spectroscopy by Continuum Soft X-ray Emission from a Short Pulse Laser-produced Plasma

EXAFS Spectroscopy by Continuum Soft X-ray Emission from a Short Pulse Laser-produced Plasma

Laser-Fusion Program Semiannual Report: January--June 1972.

Direct-drive inertial confinement fusion: A review

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