ZAPP: An Inexpensive Versatile X-Ray Source

The Z-pinch atomic physics project (ZAPP) in E-Division at the Lawrence Livermore Laboratory has been established to study the physics of high temperature high density plasmas. Using a linear hollow gas puff or a cylindrical wire array we can obtain electron temperatures in the keV region and densities of 1020 -1022/cm3 for virtually any element or mixtures of elements. At the center of this project is a 100 kV, 55 kJ capacitor bank which discharges through low inductance switches and transmission lines into the load developing peak currents in the 2.5 × 106 amp range. One of our goals is to have all major diagnostics temporally and spatially resolved. Included in this list are pinhole photography, grazing incidence and bent crystal spectroscopy, laser interferometry and holography, and pulsed laser scattering. We have also implemented an array of PIN diodes, XRD detectors and Rogowski coils. With a clean, repeatable, well diagnosed plasma we can address a wealth of questions concerning both plasma and atomic physics. The main experimental emphasis centers on the investigation of plasma properties such as line broadening and shifting of spectral lines and in general testing the ability of existing codes to predict observed spectra of both lines and continuum radiation. Other plasma properties to be studied are the formation of hot spots and the production of stabilized plasmas. Atomic physics experiments include the study of radiative and relativistic effects in highly stripped heavy ions, radiation transport phenomena, collisional excitation rates and level populations to test inversion schemes.