부산대학교 도서관

The Microhexcavity Panel ( muHex) is a novel gaseous micropattern particledetector comprised of a dense array of close-packed hexagonal pixels, eachoperating as an independent detection unit for ionizing radiation. It is asecond generation detector derived from plasma panel detectors and microcavitydetectors. The muHex is under development to be deployed as a scalable, fasttiming (ns) and hermetically sealed gaseous tracking detector with high rate (> 100 KHz/cm^2 ) capability. The devices reported here were fabricated as 16 x16 pixel arrays of 2 mm edge-to-edge, 1 mm deep hexagonal cells embedded in athin, 1.4 mm glass-ceramic wafer. Cell walls are metalized cathodes, connectedto high voltage bus lines through conductive vias. Anodes are small, 457 microndiameter metal discs screen printed on the upper substrate. The detectors arefilled with an operating gas to near 1 atm and then closed with a shut-offvalve. They have been operated in both avalanche mode and gas dischargedevices, producing mV to volt level signals with about 1 to 3 ns rise times.Operation in discharge mode is enabled by high impedance quench resistors onthe high voltage bus at each pixel site. Results indicate that each individualpixel behaves as an isolated detection unit with high single pixel intrinsicefficiency to both beta's from radioactive sources and to cosmic ray muons.Continuous avalanche mode operation over several days at hit rates over 300KHz/cm^2 with no gas flow have been observed. Measurements of pixel isolation,timing response, efficiency, hit rate and rate stability are reported.