A 100-kV, 2-kA, 2.5-/spl mu/S pulser for developing and calibrating long-pulse diagnostics

Abstract

The development of voltage and current probes for measuring an electron beam's current and position associated with several microsecond-long pulses from advanced linear induction accelerators requires a precision pulser that can deliver both high voltages and high currents to a diagnostics test line. Seven-stage, type-E PFNs have been utilized in both a transformer and 4-stage Marx (plus/minus) configuration. The resulting 50-ohm pulser delivers to the test line a repeatable 100 kV, /spl sim/2 /spl mu/s flat-top (/spl plusmn/1%), 2.5 /spl mu/s FWHM pulse with a rise time of 500 ns and 175 ns for the transformer and Marx options, respectively. Methods of reducing the rise time for both options are discussed and modeled. The coaxial test line is insulated at up to two atmospheres with SF/sub 6/ and includes two transition regions to hold and test different diameter beam current and position monitors (BPMs). The center conductor incorporates both translation and tip/tilt with an accuracy of 100 /spl mu/m. Finally, the line is terminated in a matched radial resistor that provides a planar region at fields up to 40 kV/cm for the testing of voltage probes. Both the transformer and Marx options are modeled and compared to experimental results.