K-shell X-ray yield enhancement from Z-pinches using element mixtures of similar atomic number

Summary form only given, as follows. In recent experiments on the 4-MA, 6-TW Double-EAGLE pulse generator we have increased the K-shell X-ray emission from aluminum wire array Z-pinches by coating the wires with magnesium and/or silicon. Mg-coated aluminum wires gave yield increases of >50% over that of uncoated aluminum wires, and Mg/Si-coated wires presently under test are expected to increase the yield by 100%. Analysis of the time-resolved spectral data shows that two effects contribute to the increased yield. First, the multi-element mixture reduces the opacity of the strongest emission lines, thus increasing the probability of photon escape. Second, the coating plasma reaches the pinch axis earlier, forming a core that is compressed and heated by the imploding mass of aluminum. Since the He-/spl alpha/ and Ly-/spl alpha/ radiation from the core is not absorbed by the outer aluminum, the X-ray yields are increased.