No Arabic abstract
The microhexcavity plasma panel detector is a type of gaseous particle detector consisting of a close-packed array of millimeter-size hexagonal cells. The cells are biased to operate in Geiger mode where each cell functions as an independent detection unit. The response of the detector to ionizing radiation was investigated using low-energy radioactive $ beta $ sources and cosmic ray muons. Efficiency measurements were conducted with cosmic ray muons in conjunction with a scintillator hodoscope. The rate response and signals obtained from the microhexcavity detector filled with Penning gas mixture at atmospheric pressure are herein described. The relative pixel efficiency, after allowing for ion-pair formation in the gas volume, is 96.8 $ pm $ 4.4$ % $ for operation of the detector above an applied high voltage of 1000 V.
Plasma panel detectors are a variant of micropattern detectors that are sensitive to ionizing radiation. They are motivated by the design and operation of plasma display panels. The detectors consist of arrays of electrically and optically isolated pixels defined by metallized cavities embedded in a dielectric substrate. These are hermetically sealed gaseous detectors that use exclusively non-hydrocarbon gas mixtures. The newest variant of these closed-architecture detectors is known as the Microhexcavity plasma panel detector ($mu$Hex) consisting of 2 mm wide, regular close-packed hexagonal pixels each with a circular thick-film anode. The fabrication, staging, and operation of these detectors is described. Initial tests with the $mu$Hex detectors operated in Geiger mode yield Volt-level signals in the presence of ionizing radiation. The spontaneous discharge rate in the absence of a source is roughly 3-4 orders of magnitude lower compared to the rates measured using low energy betas.
A new type of gaseous micropattern particle detector based on a closed-cell microcavity plasma panel sensor is reported. The first device was fabricated with 1 x 1 x 2 mm cells. It has shown very clean signals of 0.6 to 2.5 volt amplitude, fast rise time of approximately 2 ns and FWHM of about 2 ns with very uniform signal shapes across all pixels. From initial measurements with beta particles from a radioactive source, a maximum pixel efficiency of greater than 95% is calculated, for operation of the detector over a 100V wide span of high voltages (HV). Over this same HV range, the background rate per pixel was measured to be 3 to 4 orders of magnitude lower than the rate with the cell illuminated by the beta source. Pixel-to-pixel count rate uniformity is within 3% and stable within 3% for many days. The time resolution is 2.4 ns, and a very low cell-to-cell crosstalk has been measured between cells separated by 2 mm.
This article reports on the development and experimental results of commercial plasma display panels adapted for their potential use as micropattern gas radiation detectors. The plasma panel sensors (PPS) design an materials include glass substrates, metal electrodes and inert gas mixtures which provide a physically robust, hermetically-sealed device. Plasma display panels used as detectors were tested with cosmic ray muons, beta rays and gamma rays, protons and thermal neutrons. The results demonstrated rise times and time resolution of a few nanoseconds, as well as sub-millimeter spatial resolution compatible with the pixel pitch.
The Microhexcavity Panel ( muHex) is a novel gaseous micropattern particle detector comprised of a dense array of close-packed hexagonal pixels, each operating as an independent detection unit for ionizing radiation. It is a second generation detector derived from plasma panel detectors and microcavity detectors. The muHex is under development to be deployed as a scalable, fast timing (ns) and hermetically sealed gaseous tracking detector with high rate ( > 100 KHz/cm^2 ) capability. The devices reported here were fabricated as 16 x 16 pixel arrays of 2 mm edge-to-edge, 1 mm deep hexagonal cells embedded in a thin, 1.4 mm glass-ceramic wafer. Cell walls are metalized cathodes, connected to high voltage bus lines through conductive vias. Anodes are small, 457 micron diameter metal discs screen printed on the upper substrate. The detectors are filled with an operating gas to near 1 atm and then closed with a shut-off valve. They have been operated in both avalanche mode and gas discharge devices, 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 on the high voltage bus at each pixel site. Results indicate that each individual pixel behaves as an isolated detection unit with high single pixel intrinsic efficiency to both betas from radioactive sources and to cosmic ray muons. Continuous avalanche mode operation over several days at hit rates over 300 KHz/cm^2 with no gas flow have been observed. Measurements of pixel isolation, timing response, efficiency, hit rate and rate stability are reported.
A radiation detector based on plasma display panel technology, which is the principal component of plasma television displays is presented. Plasma Panel Sensor (PPS) technology is a variant of micropattern gas radiation detectors. The PPS is conceived as an array of sealed plasma discharge gas cells which can be used for fast response (O(5ns) per pixel), high spatial resolution detection (pixel pitch can be less than 100 micrometer) of ionizing and minimum ionizing particles. The PPS is assembled from non-reactive, intrinsically radiation-hard materials: glass substrates, metal electrodes and inert gas mixtures. We report on the PPS development program, including simulations and design and the first laboratory studies which demonstrate the usage of plasma display panels in measurements of cosmic ray muons, as well as the expansion of experimental results on the detection of betas from radioactive sources.