Scaling of K-shell emission from Z-pinches: Z to ZR

Summary form only given. Experiments in the last few years at the 20 MA Z Accelerator have produced significant K-shell X-ray output from a variety of initial load materials, including argon (3 keV, >300 kJ), titanium (4.8 keV, 100 kJ), stainless steel (7 keV, >50 kJ), and copper (8.4 keV, 20 kJ). K-shell scaling theories, developed at NRL, were benchmarked against the K-shell emission data from lower current facilities and photon energies up to 3 keV. This theory identifies the initial load conditions necessary to get enough mass to implode at a high enough velocity to achieve the high plasma temperatures and densities required for K-shell emission. For the conditions available at Z, efficient K-shell emission up to 5 keV is expected. The experimental results from the various sources at Z have not only demonstrated the heuristic validity of K-shell scaling models, but have provided the data to fine tune the models for higher photon energies. The upgrade of the Z accelerator to ZR, which will provide 26 MA to a Z-pinch load, should extend the region of efficient K-shell production to include photon energies up to 7 keV. This will increase the radiated K-shell output for sources previously fielded at Z, but will also extend the range of photon energies where measurable radiation can be observed, likely up to 13 keV. In this paper, the results of K-shell scaling experiments from Z will be presented, as well as the expected scaling of these sources to ZR. Plasma conditions from the Z experiments will be discussed within the context of efficient K-shell production, which helps identify the appropriate plasma conditions necessary for efficient production at ZR. Calculated results for expected ZR outputs will be presented