X-RAY TEMPORAL, SPATIAL AND SPECTRAL STUDY OF 0.9 MA X-PINCH Ti, Fe, Mo, W AND Pt RADIATION SOURCES. ENERGETIC ELECTRON BEAM AND HARD X-RAY GENERATION. V.L. Kantsyrev, A.S. Shlyaptseva, B.S. Bauer, D.A. Fedin, R. Presura, S. Fuelling, S. Hansen, S. Batie, A. Oxner, H. Faretto, N. Ouart, S. Keely, H. LeBeau, D. Chamberlain The Physics Department, the Nevada Terawatt Facility of the University of Nevada Reno, MS 220, Reno, NV 89557-0058, USA Abstract The x-ray emission of Ti, Fe, Mo, W, and Pt x-pinches currently being studied at the Nevada Terawatt Facility (0.9-1.0 MA, 100 ns). New x-ray diagnostics for time-resolved spectroscopy and imaging has been developed and used in x-pinch experiments. Total x-ray/ EUV yield was more than 10 kJ. The minimum x-ray pulse duration was 1.1 ns. For Ti, Mo and W it was observed that x-ray pulses occurred in two or three groups in the narrow time intervals after the start of the current. Most compact emitting region has been observed for a planar-loop Mo x-pinch. Strong jets were observed (Ti, Fe, Mo) directed toward the discharge axis, perpendicular to the wires. A structure of x-pinch includes energetic electron beams directed toward the anode and along wires. A pulse anisotropic hard x-ray radiation was observed moving upwards along the axial axis with an energy of several hundred keV (Mo). The size of the source was smaller than 1 mm. I. INTRODUCTION The high current x-pinch [1] is a good candidate for developing a new (harder) x-ray backlighter, for testing x-ray spectropolarimetry [2] (a powerful new tool for studying the anisotropy of high-temperature plasmas), for examining the final stage of the MHD instability, and other applications. The main directions of NTF x- pinches research are: studying of the dynamics of plasma implosion and determinations of plasma conditions in x-pinch that lead to generations of short x-ray pulses; studying of the influence of strong energetic electron beams on the parameters of plasmas; and studying of x-pinch plasma anisotropy. II. PLASMA DIAGNOSTIC RESEARCH Plasma diagnostic research at NTF [1,2] includes: a) development of x-ray and EUV (extreme ultraviolet) plasma time- and spatial-resolved spectroscopic, imaging, polarimetric, and x-ray backlighter systems, fast x-ray/hard x-ray detectors; b) measurements of temperature and density of plasma that based on theoretical modeling of K-, L-, and M-shell ions x-ray spectra [3]; c) experimental polarization x-ray measurements and the theoretical polarization study [2, 3] including influence of electron beams in plasma on linear x-ray spectra, measurements of temperature, density and inner magnetic field in z pinch plasma. The NTF diagnostics includes 12 devices (beginning of development-1997 [4]): side-on one-dimensional time-gated spectrometer (1DXIS [1]); side-on time- resolved “Polychromator” spectrometer with a transmission grating spectrometer (TGS) [5]; side-on one-dimensional x-ray imaging time-integrated crystal spectrometer with a survey pinhole camera [1]; side-on and end-on one-dimensional x-ray imaging time- integrated polarimeter-spectrometers [2]; side-on multichannel time-gated pinhole camera (GXI) [1]; side-on time-integrated high-resolution pinhole camera; end-on time-integrated super-high-resolution pinhole camera; side-on filtered fast PCD and XRD detectors, and a Ni x-ray bolometer [1]; end- and side-on hard x- ray time–integrated imaging detectors with filtered x- ray films; and end-on hard x-ray detector. Side-on two- dimensional glass-capillary imaging spectrometer (2DXIS) [1, 6] decomposes an image into pixels, separates and spectrally disperses these pixels, and records spectra with a time-gate MCP intensifier. The device is under testing at the NTF. Side-on and end-on hard x-ray fast detectors with spatial resolution capability and a side-on EUV imaging diagnostic beamline are under development. The diffraction limitation in spatial resolution for side-on diagnostics due to lack of a minimum distance from plasma to detectors (30-60 cm) was 20-25μm at λ=10 Å and 5-10 μm at λ=1 Å. All the NTF experiments were proved under vacuum better than 5x10 -6 torr. Vacuum beamlines have permanent magnets to protect the x-ray devices against the damage from z-pinch ion beams. III. EXPERIMENTAL RESULTS X-pinches were made by positioning two thin, straight, crossed wires between the cathode and the anode of the Zebra pulsed-power generator, with wires contact on the axis of the cathode-anode gap. Two configurations of x-pinches were tested: twisted wires and planar-loop. Other loads for comparison with 0-7803-7120-8/02/$17.00 ' 2002 IEEE