X-ray temporal, spatial and spectral study of 0.9 MA X-pinch Ti, Fe, Mo, W and Pt radiation sources

Summary form only given. X-ray emission of Ti, Fe, Mo, W and Pt X-pinches at the Nevada Terawatt Facility (1 MA, 220 kJ) is studied. The energy and time scaling of X-rays were measured by a PCD and an XRD. A Ni bolometer (from SNL) measured the total X-ray/EUV energy radiated to be more than 10 kJ(4-5 kJ in L-shell and 30J in K-shell). Minimum duration of x-ray pulses were: from 1.5-2.5 ns for Ti and Fe K-shell radiation to 1-1.2 ns for Mo L-shell and W and Pt M-shell radiation. Typically, the emitting X-pinch region includes 1-4 hot bright spots (each smaller than the 30-micron resolution of the pinhole camera). It was shown that a X-ray image of the source moved a distance of 1-3 mm along the symmetry axis during the discharge with a maximum speed of 5/spl times/10(7)cm/s. Strong jets are observed (mostly in softer than Ti or Fe K-shell continuum emission) directed toward the X-pinch axis, perpendicular to the wires. It was observed that a strong electron beam is not only directed to the center of the X-pinch anode, but also toward the anode ends of the wires. Such a beam influences the plasma X-ray spectra (see A.S. Shlyaptseva et al.). A strong hard X-ray beam was observed upwards along the axial axis with an energy between 50 and several hundred of keV. Most X-ray spectra were recorded with time-integrated one-dimensional convex crystal spectrographs, spectropolarimeters (wavelengths shorter than 2.5 nm), and a time-integrated one-dimensional transmission-grating spectrometer (wavelengths from 2.0 to 8.0 nm). Experiments with the "Polychromator" have shown that often the time dependence of the intensity of selected spectral lines (for example, 0.261 nm He-like Ti or 0.185 nm He-like Fe) is different from the time dependence of short wavelength PCD signals.