Time-resolved 1-10 keV crystal spectrometer for the Z machine at Sandia national laboratories

We have designed, fabricated, calibrated, and fielded a fast, time-resolved 1-10 keV crystal spectrometer to observe the evolution of wire pinch spectra at the Z machine at Sandia national laboratories. The instrument has two convex cylindrical crystals (PET and KAP). Both crystals Bragg reflect X-rays into an array of ten silicon diodes, providing continuous spectral coverage in twenty channels from 1.0 to 10 keV. The spectral response of the instrument has been calibrated from 1.0 to 6.3 keV at beamline X8A at the national synchrotron light source. The time response of the 1-mm/sup 2/ silicon detectors was measured with the pulsed X-ray source at Bechtel Nevada´s Los Alamos Operations, where 2-nanosecond full-width half-maximum (FWHM) waveforms with 700-picosecond rise times typically were observed. The spectrometer has been fielded recently on several experimental runs at the Z Machine. In this paper, we present the time-resolved spectra resulting from the implosions of double-nested tungsten wire arrays onto 5-mm diameter foam cylinders. We also show the results obtained for a double-nested stainless steel wire array with no target cylinder. The spectrometer was located at the end of a 7.1-meter beamline on line-of sight (LOS) 21/22, at an angle 12/spl deg/ above the equatorial plane, and was protected from the debris field by a customized dual-slit fast valve. The soft detector channels below 2.0 keV recorded large signals at pinch tune coinciding with signals recorded on vacuum X-ray diodes (XRDs). On experiment Z993, the spectrometer channels recorded a second pulse with a hard X-ray emission spectrum several nanoseconds after pinch time.