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A review is given of recent developments in energy-dispersive x-ray emission spectroscopy, with the aim of providing both an introductory and usefully practical look at this innovative field. The review begins with the first principles of x-ray production and observation, including a brief comparison of the performance capabilities of different types of detectors, but then specializes to a major extent in solid state x-ray spectrometers, which have led to the most significant new developments and applications. Evidence is presented which suggests that we are nearing an asymptotic limit in the attainment of ever better resolution with these types of systems. Applications that have been made possible by significant improvements in system resolution are discussed, but in the context of the need for a realistic appraisal of over-all system requirements. The great advantages offered by the marriage of silicon x-ray spectrometers to scanning electron microscopes and electron microprobe analyzers are reviewed and illustrated.

A Magnetic Recoil Spectrometer (MRS) has been built and successfully used at OMEGA for measurements of down-scattered neutrons (DS-n), from which areal density (ρR) in both warm-capsule and cryogenic-DT implosions have been inferred. Another MRS is currently being commissioned on the National Ignition Facility (NIF) for diagnosing low-yield tritium-hydrogen-deuterium (THD) implosions and high-yield DT implosions. As CR-39 detectors are used in the MRS, the principal sources of background are neutron-induced tracks and intrinsic tracks (defects in the CR-39). The Coincidence Counting Technique (CCT) was developed to reduce these types of background tracks to the required level for the DS-n measurements at OMEGA and the NIF. Using this technique, it has been demonstrated that the number background tracks is reduced by a couple of orders of magnitude, which exceeds the requirement for the DS-n measurements at both facilities. a) Also Visiting Senior Scientist at the Laboratory for Laser Energetics, University of Rochester.