Spectral output of z-machine implosions.

[摘要] Sandia National Laboratories Z-machine has developed into a reproducible, high power (>200 TW), high temperature (>200 eV) driver for radiation source with a bolometric temperature of about 200 eV. By surrounding the z-pinch implosion with a vacuum hohlraum a nearly Planckian source of about 140 eV temperature is created with peak radiation power of about 200 terawatts and integrated energy of 2 megajoules or more. In this energy rich environment we can field a dozen experiments all being driven by an identical source. In addition to 'standard' vacuum hohlraums we also use dynamic hohlraums consisting with two nested wire arrays converging onto an axially centered foam cylinder. Radiation flowing from the ends on the cylinder indicates a Planckian source temperature well over 200 eV. Only two experiments can be fielded on a dynamic hohlraum (one on each end) but the higher source temperature justifies the added complexity of the set-up. We routinely use arrays of filtered silicon photodiodes (SiD) and filtered photocathode x-ray diodes (XRD) to determine the temperature of the source. Three different techniques for unfolding spectra from the XRD and SiD detector data being used. They are: (1) Treat each detector independently and find the Planckian temperture for a given source size and solid angle that would give the measured detector signal, (2) Use all detector signals and detector spectral responses simultaneously and find a spectrum that best fits the observed data, (3) Use all detector signals and averaged detector spectral responses and find a histogram spectrum that best fits the observed data. When used as complementary set of analysis tools these techniques generate remarkably consistent results showing nearly Planckian behavior on our vacuum hohlraum experiments.

[发布机构] Technical Information Center Oak Ridge Tennessee

[学科分类] 工程和技术（综合）

[关键词] Laser implosions;Pulsed power;Pinch devices;Spectra;Hohbraums