This article presents a review of X-ray spectroscopic diagnostic and measurement techniques as applied to laser plasma interaction and laser fusion studies. As a matter of definition we restrict our attention to the range of a several hundred eV to about 100 keV. We deal with both the basic measurement concepts and the instrumental techniques. First a brief review of the physical phenomena and parameter ranges involved is given. We then deal with specific X-ray spectroscopic instruments and methods that are useful in laser plasma X-ray spectroscopy. A discussion is given of various modeling techniques and how they can be compared with experimental measurements.

Recent technological developments have resulted in sub 100 ps shutter times of X-ray cameras that are based on the gating of microchannel plates. Moreover, these cameras are reliable enough to be used on large experimental systems. A review is given of the development of gated proximity focused detectors and of the factors affecting their performance.

State of the art capabilities in soft X-ray lenses, multilayer mirrors, beamsplitters, and synthetically generated holograms are reviewed. Application of these capabilities in recent X-ray laser cavity experiments, and to the development of a soft X-ray interferometer and a high intensity (≥1013 watt/cm2) soft X-ray laser are discussed.

Radiation-induced conductivity (RIC) is a generalized term for photoconductivity expanded to include nonelectromagnetic radiation. RIC offers several distinct advantages for the detection of high-energy radiation: (i) the speed of response of a detector is determined by a bulk property of the material, the carrier lifetime; (ii) the detector can be directly illuminated by the signal radiation-no dead layer; and (iii) the selection of the detector material and its geometry is very flexible. This paper will discuss the principles of RIC for X rays and neutrons, the fabrication of detectors, and applications. RIC detectors have been fabricated from Si, InP, GaAs, and diamond. Bulk and thin film materials have been used. The carrier lifetime was varied by the introduction of trapping sites in the material. This can be done in the material production process in the case of doping (e.g., Fe in InP) and thin films or produced from radiation damage of a pure crystalline material. Lifetimes as short as a few picoseconds have been observed. A variety of detectors have been tested using pulsed optical, X ray, and neutron sources. Absolute sensitivities and temporal response has been measured and compared to theoretical models of the detector's performance for both X rays and neutrons. Finally, applications of these detectors to inertial confinement fusion measurement will be shown.

A camera has been developed that directly measures the deuterium-tritium burn region of laser-driven inertial confinement fusion targets. Images are formed by 14-MeV thermonuclear neutrons emitted from the targets. Our demonstration instrument is based on a coded-aperture imaging technique known as penumbral imaging, and has produced images of high-yield (> 1012 neutrons) direct-drive targets with resolutions of 80 μm. The camera consists of four major components: the penumbral aperture, alignment hardware, detector system, and image analysis software.

Fuel areal density, 〈ρR〉, is a fundamental quantity for ICF implosions. For current and future targets, areal densities are large enough that a variety of neutron based diagnostic techniques can be used to determine fuel 〈ρR〉. These include measurements based on the secondary production of DT neutrons from initially pure deuterium fuel and, for higher 〈ρR〉 values, techniques utilizing high energy tertiary neutrons or lower energy scattered neutrons. This paper describes these techniques and gives an overview of the current experimental status.

X-ray spectroscopical and microscopical methods are used for the determination of the spectral and spatial distribution of X-ray intensity of laser-produced plasmas. The use of Bragg reflections of two-dimensionally bent crystals enables the X-ray microscopical imaging in narrow spectral ranges (Δλ/λ = 10−4 to 10−2) with wavelengths 0.1 nm < λ > 2.6 nm. It is possible to adapt, in the X-ray microscope, the distances, magnification, position, and width of the spectral window to the special conditions of the laser facility. Manufacturing and testing of the two-dimensionally bent crystals requires a great deal of effort. It was demonstrated that a spatial resolution of about 5 μm was achieved, and that the experimentally determined reflectivity was found to be in close agreement with the dynamical theory of X-ray interferences. Due to high luminosity of the X-ray microscope, in experiments with laser-produced plasmas it was necessary to attenuate the radiation with aperture-limiting diaphragms or filters down to 0.01–1% of the original intensity in the case of a magnification of about one. Emission of the resonance line W 1–2, the intercombination line of helium-like ions, and Lyman alpha line were imaged simultaneously with a three-channel microscope. Such images form the foundation for establishing the Ne(r), Tz(r) maps.

Analyses are given for beam generations of three kinds of charged particles: electrons, light ions, and heavy ions. The electron beam oscillates in a dense plasma irradiated by a strong laser light. When the frequency of laser light is high and its intensity is large, the acceleration of oscillating electrons becomes large and the electrons radiate electromagnetic waves. As the reaction, the electrons feel a damping force, whose effect on oscillating electron motion is investigated first. Second, the electron beam induces the strong electromagnetic field by its self-induced electric current density when the electron number density is high. The induced electric field reduces the oscillation motion and deforms the beam.

In the case of a light ion beam, the electrostatic field, induced by the beam charge, as well as the electromagnetic field, induced by the beam current, affects the beam motion. The total energy of the magnetic field surrounding the beam is rather small in comparison with its kinetic energy.

In the case of heavy ion beams the beam charge at the leading edge is much smaller in comparison with the case of light ion beams when the heavy ion beam propagates in the background plasma. Thus, the induced electrostatic and electromagnetic fields do not much affect the beam propagation.

Some peculiarities of using negative ions for accelerators and CTR are examined. Highpower beams of fast atoms obtained by charge exchange of negative ions can have advantages over positive ion beams for inertial confinement fusion (ICF) since they do not experience any deviations, instabilities, and scattering. H− current up to 7 kA in a 100–200 ns pulse with densities up to 200 Å/cm2 and a voltage of 0.8 MV were obtained in experiments on magnetically insulated diodes at the Lebedev Physical Institute. Diagnostics of high-power H− beams are described. Experimental results on cathode plasma formation by surface discharge on a dielectric initiated by a bipolar prepulse or by laser illumination are presented. The dependence of H− yield on cathode current was determined and experiments on plasma stabilization are described. It is concluded that 1 kÅ/cm2 of H− can be obtained.