MICROCHANNEL PLATES IN ADVANCED WIND-TUNNEL INSTRUMENTATION

MICROCHANNEL PLATE INNOVATIONS ARE DESCRIBED WHICH WILL ASSIST IN THE DEVELOPMENT OF ADVANCED WIND TUNNEL INSTRUMENTATION. THE INNOVATIONS WILL IMPROVE INSTRUMENTAL RESPONSE FOR: (1) THE MASS SPECTROMETRIC MEASUREMENT OF BOUNDARY LAYER GASSES; (2) TEMPERATURE MEASUREMENT OF GASSES; (3) HIGH SENSITIVITY THERMAL IMAGING OF TRANSIENTS; (4) OPTICAL SPECTROSCOPY AND PHOTOGRAPHY FOR FLOW VISUALIZATION IN HIGH ENTHALPY TEST FACILITIES. INNOVATIONSWHICH MUST BE DEVELOPED TO MAKE SUCH INSTRUMENTS PRACTICAL INCLUDE DEVELOPING TECHNIQUES TO REDUCE THE FREQUENCY OF SPURIOUS ELECTRON PULSE EMISSION FROM MICROCHANNEL PLATES WHICH CONSTITUTE BACKGROUND NOISE AND SECONDLY TO ACCELERATETHE CHANNEL RECOVEY PROCESS, THEREBY RAISING THE PERMISSIBLEMAXIMUM SIGNAL FREQUENCY. IT IS SHOWN THAT TOGETHER THESE TECHNIQUES CAN LEAD TO A FACTOR OF 1000 GROWTH IN DYNAMIC RANGE. IT IS ALSO SUGGESTED THAT THE EFFORT GALILEO IS ALREADY DEVOTING TO NEW HIGH-SILICA MATERIALS FOR MICROCHANNEL PLATES AND OPTICAL FIBERS WILL FURTHER ENHANCE THE USEFULNESS OF THESE INSTRUMENTS BY PERMITTING HIGHER TEMPERATURE OPERATION.