Radiation Power Measurements of Dynamic Hohlraums on the Z-Machine

Summary form only given. Critical parameters required to perform a radiation-flow experiment on a Z-pinch are the drive radiation spectrum, intensity, and time history. With the advent of the dynamic hohlraum source at the Sandia National Laboratories Z-machine the diagnostic access to monitor the drive radiation was limited to one end of a cylindrical source. Initial comparisons showed large asymmetries in intensity and time history between the two ends of a cylindrical TPX foam implosion target. Spectral analysis showed tungsten from the imploding wire array was blocking the radiation exit hole (REH) on the cathode end of the pinch. A 3 mm tall pedestal placed on the cathode end of the TPX cylinder has restored the time and intensity profile to match the output from the anode end REH. Profiles measured from some 30 shots are presented which illustrate the evolution of the diagnostic technique into a reliable power monitoring method. We have installed computer software at the Z-machine which allows spectral deconvolution and power calculations to be performed within 30 minutes after firing the machine. This rapid data analysis identifies diagnostic problems and allows adjustments to be made in experiment parameters for the following day´s shot. We also present initial results from a small, 1 mm diameter, hole placed in the coupling funnel that connects the anode side REH with a radiation flow experiment. Expectations of correlating the reliable cathode end 4 mm diameter REH measurement with the small anode end REH monitor hole have proven to be both encouraging and frustrating