Species Selective Pressure Gauge for High Performance Divertors

50326-98-I Species Selective Pressure Gauge for High Performance Divertors--HY-Tech Research Corporation, 104 Centre Court, Radford Industrial Center, Radford, VA 24141-5123; (540) 639-4019 Dr. C. Christopher Klepper, Principal Investigator Dr. Robert C. Hazelton, Business Official DOE Grant No. DE-FG02-98ER82592 Amount: $55,008 The species selective penning gauge diagnostic, presently used for helium and tritium concentration measurements in, for instance, the divertor region of the DIII-D tokamak reactor, begins to saturate in the 1-5m Torr range, which is lower than the pressure of most interest. In this project, a more economical and tritium-compatible solution to differential pumping will be developed. It is based on extending the saturation limit by optimizing the cathode material, anode-cathode spacing and shape, and the applied magnetic field. In Phase I, an experimental version of the commercial penning gauge will be constructed with exchangeable components. The saturation limit will be scaled to the changeable parameters and a prototype design will be produced. Commercial Applications and Other Benefits as described by the awardee: Such a device could be an important feedback control sensor for eventual fusion reactor fueling. The extended pressure range should also allow the device to be used as a sensor for plasma processing of effluent (for feedback or pollution control)._