X‐pinch experiments using conichrome alloy wires were implemented on 1MA COBRA facility at Cornell University. X‐ray spectral and imaging data were collected. In particular, the spatially‐resolved, time‐integrated x‐ray line K‐shell and L‐shell spectra of Cr, Co, and Ni ions from these alloy X‐pinches were recorded in one pulse using a mica crystal spectrometer. Non‐LTE kinetic models were applied to model these spectra. The results of this modeling are presented and the interpretation of K‐shell and L‐shell Cr, Co, and Ni as well as L‐shell Mo spectra from conichrome alloy X‐pinches are discussed.

Experiments with X-pinches made with both Mo and W wires have been performed on 1-MA pulsed power generators at Cornell University and University of Nevada, Reno. X-ray images and spectra have been studied and compared for three different configurations of X-pinch loads with Mo and W wires. For all X-pinches, the image size decreases with decreasing wavelength and photoconducting diode (PCD) signals show multiple bursts except for one variant of the mixed Mo and W configurations. Time-gated, as well as time-integrated, images indicate the presence of radiation from energetic electrons. Previous experience with application of L-shell Mo modeling to various Z- and X-pinch experiments helped to determine plasma parameters in the X-pinches studied here, and permitted identification of M-shell W spectral features useful for plasma parameter estimation

The experiments reported here were designed to test X-pinch wire-loading configurations using a simple plastic frame that might enable the X-pinch wires to be changed under vacuum after a pulse. Several frame configurations and materials were tested, some of which suffered from early surface flashover and current shunting away from the X-pinch. Fiberglass frames proved to be successful both in minimizing the current shunting up to the time of the X-pinch X-ray burst and, in most tests, in substantially reducing X-ray emission from energetic electrons and secondary soft X-ray bursts following the first X-ray burst. Both of these features are beneficial for using X-pinches for point-projection radiography as well as for recording X-ray spectra from the X-pinches or other nearby plasmas

X-pinch experiments using combined Mo and W wires were implemented on the I MA Cornell University (CU) COBRA and University of Nevada, Reno (UNR) ZEBRA facilities. Spatially-resolved and integrated x-ray spectral data and time integrated and time-gated pinhole x-ray images accumulated in these X-pinch experiments are analyzed. In particular, x-ray L-shell spectra of Mo ions and M-shell spectra of W ions have been studied. A non-LTE collisional-radiative (CR) atomic kinetic model of Mo, successfully applied before to interpret UNR and CU x-ray spectra from Mo X-pinches, was used here to provide plasma parameters from L-shell Mo radiation from the combined (W/Mo) X-pinches. The recently developed non-LTE CR model of W based on FAC atomic structure code data has been applied to identify and diagnose the spectral features of W ions and to provide parameters of the plasma from M-shell W radiation from W/Mo X-pinches. As a result, the radiative properties of W/Mo X-pinches produced on two I MA university-scale pulsed power facilities are analyzed and compared.

Summary form only given. Electron beams in X-pinches generated at the CU XP (current 0.45 MA, 50 ns rise time) facility have been studied from measurements of X-rays >9 keV with 1 ns time-resolved filtered and collimated hard X-ray Si diodes. Early three types of electron beams were observed (V. Kantsyrev et al., Rev. Sci. Instr. 75, 3708 (2003)) in X-pinches. Spatial resolution was 0.4 of the anode-cathode X-pinch gap. One diode was pointed at a cross-wire point and another at a region of wires contacts with an X-pinch anode. Softer X-rays were monitored by a PCD detector. Pinhole cameras and an X-ray spectrometer were also applied. During the most discharges, in the cross-wire region the first (1-2 ns duration and correlated with the moment of the first plasma implosion) and the second (2.5-10 ns duration and weakly correlated with soft X-ray bursts) types of electron beams appear. In the anode region, the second and the third (10-30 ns duration, not correlated with any of soft X-ray bursts) types of electron beams were observed. Typically, the intensity of electron beams in a center part of an X-pinch, that appear immediately after the first softer X-ray burst, decreases with current dropping. In opposite, in most discharges, the anode electron beams start about 5-20 ns after the first softer X-ray burst and reached the maximum intensity 20-30 ns later. The different mechanisms of X-pinch electron beams generation are discussed