Direct comparison of wire, foil, and hybrid X-pinches on a 200 kA, 150 ns current driver

Wire X-pinches (WXPs) have been studied comprehensively as fast ( similar to 1ns pulse width), small ( similar to 1 mu m) x-ray sources, created by twisting two or more fine wires into an X to produce a localized region of extreme magnetic pressure at the cross-point. Recently, two alternatives to the traditional WXP have arisen: the hybrid X-pinch (HXP), composed of two conical electrodes bridged by a thin wire or capillary, and the laser-cut foil X-pinch (LCXP), cut from a thin foil using a laser. We present a comparison of copper wire, hybrid, and laser-cut foil X-pinches on a single experimental platform: UC San Diego's similar to 200kA, 150ns rise time GenASIS driver. All configurations produced 1-2ns pulse width, <= 5 mu m soft x-ray (Cu L-shell, similar to 1keV) sources (resolutions diagnostically limited) with comparable fluxes. WXP results varied with linear mass and wire count, but consistently showed separate pinch and electron-beam-driven sources. LCXPs produced the brightest ( similar to 1MW), smallest ( <= 5 mu m) Cu K-shell sources, and spectroscopic data showed both H-like Cu K alpha lines indicative of source temperatures >= 2keV, and cold K alpha ( similar to 8050eV) characteristic of electron beam generated sources, which were not separately resolved on other diagnostics (within 1-2ns and <= 200 mu m). HXPs produced minimal K-shell emission and reliably single, bright, and small L-shell sources after modifications to shape the early current pulse through them. Benefits and drawbacks for each configuration are discussed to provide potential X-pinch users with the information required to choose the configuration best suited to their needs.

Automated summary

The study compared copper wire, hybrid, and laser-cut foil X-pinches on a single experimental platform and found that they all produced similar soft X-ray spectra, with LCXPs producing the brightest Cu K-shell sources and HXPs being suitable for shaping to produce single, bright, and small L-shell sources.