Photoionization Front Laboratory Experiments at the OMEGA Laser Facility

Photoionization fronts are meaningful drivers of transformation for astrophysical phenomena. Generating sufficiently intense x-rays in laboratory experiments has been a difficult challenge. We attempt to create an environment relevant to astrophysical systems in which intense photon fluxes drive ionization and dynamics. Experiments at the OMEGA Laser Facility can create relevant photoionization conditions. One can generate a backlighter X-ray source through the ablation of an 860 micron diameter spherical nickel lined CH capsule. A laser irradiated gold foil generates an intense, thermal X-ray source (80-90 eV) which propagates into a gas cell filled with argon for the investigation of the Ka-absorption edge (3.203 keV). We present the preliminary results from an analytical study of the cold argon gas K-shell edge line absorption, characterized with a streak x-ray spectrometer using an RbAP crystal. We measured the K-edge of X-ray absorption spectra of argon gas using 2-4keV continuum photon energy from the capsule implosion.