The long range structure of materials is currently being studied using small angle scattering of slow ("cold") neutrons and X- rays. Local order is studied by diffraction. With the advent of stronger sources of cold neutrons, and the current situation with X-ray sources, there is a need for much higher speed of response in large area arrays. Present ion-chamber wire arrays are limited to about 40,000 cts/s TOTAL with 10% deadtime. Ratios of 10,000 cts/s PER PIXEL, with little crosstalk, would "amount to a revolution in cold-neutron physics". Curved detectors are impractical with stretched wires. The use of semiconductor sub- arrays, 5 cm square, with 5 mm square elements, would allow substantially spherical array systems. The present project will develop fast, efficient sub-arrays comprising a converter layer with 100 detectors, 100 amplifier chains and 100 scaler/readout registers located on a few slices of silicon. The present research will test the detector portion of the system and study the feasibility of the complete system.
