Evolving approaches to pulsed X-ray sources

Production of pulsed radiation in the kiloelectronvolt-to-megaelectronvolt range for simulation of nuclear weapon effects uses pulsed power generators with output powers of the order of 1-10 TW. Radiation in the high-energy (gamma and hot) part of the spectrum has been obtained using intense electron beams incident on solid targets of high-Z material to produce radiation with continuous bremsstrahlung spectra. Magnetically driven plasma implosions have been used to obtain radiation in the keV (cold) part of the spectrum, characterized by strong line emission. The efficiency of radiation, required for Defense Threat Reduction Agency tasks, relative to stored pulser energy, is only a few percent. Radiation yields in the range of 5 to 60 keV are especially low, regardless of which method of radiation production is used. This article discusses the evolving approaches to producing hot and cold X-rays, to seeking more efficient radiators of cold and warm X-rays, and to improving the spectral and temporal characteristics of the hot radiation. Integration of the pulsed power drivers, with innovative radiator load concepts, is utilized to expand the cold and hot X-ray test capability, to increase the warm X-ray yields, as well as to reduce capital costs of the test facilities.