Filtered x-ray diode diagnostics fielded on the Z accelerator for source power measurements

Filtered x-ray diode (XRD) detectors are used as primary radiation flux dia gnostics on Sandia's Z accelerator, which generates nominally a 200-TW, 2-M J, x-ray pulse. Given such flux levels and XRD sensitivities the detectors are being fielded 23 m from the source. The standard diagnostic setup and s ensitivities are discussed. Vitreous carbon photocathodes are being used to reduce the effect of hydrocarbon contamination present in the Z-machine va cuum system. Nevertheless pre- and postcalibration data taken indicate spec trally dependent changes in the sensitivity of these detectors by up to fac tors of 2 or 3. (C) 1999 American Institute of Physics. [S0034-6748(99)7040 1-6].