Bright x-ray stainless steel K-shell source development at the National Ignition Facility

• Published in: Physics of plasmas 2015-06, Vol.22 (6)
• Main Authors: May, M. J., Fournier, K. B., Colvin, J. D., Barrios, M. A., Dewald, E. L., Hohenberger, M., Moody, J., Patterson, J. R., Schneider, M., Widmann, K., Regan, S. P.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION; ATOMIC AND MOLECULAR PHYSICS; Emission; Energy conversion efficiency; Flux density; Fluxes; Ignition; Image filters; Laser deposition; Nickel; Photons; Plasma physics; Plasma temperature; Spectrometers; Stainless steel; Stainless steels; Thick walls; Tubes; X ray sources; X ray spectrometers; X-ray imaging; X-ray lasers
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/1.4922751

High x-ray conversion efficiency (XRCE) K-shell sources are being developed for high energy density experiments for use as backlighters and for the testing of materials exposed to high x-ray fluxes and fluences. Recently, sources with high XRCE in the K-shell x-ray energy range of iron and nickel were investigated at the National Ignition Facility (NIF). The x-ray conversion efficiency in the 5–9 keV spectral range was determined to be 6.8% ± 0.3%. These targets were 4.1 mm diameter, 4 mm tall hollow epoxy tubes having a 50 μm thick wall supporting a tube of 3 to 3.5 μm thick stainless steel. The NIF laser deposited ∼460 kJ of 3ω light into the target in a 140 TW, 3.3 ns square pulse. The absolute x-ray emission of the source was measured by two calibrated Dante x-ray spectrometers. Time resolved images filtered for the Fe K-shell were recorded to follow the heating of the target. Time integrated high-resolution spectra were recorded in the K-shell range.