Cathode-ray switch tubes with 100 and 256 elements

Switch tubes with 100 and 256 elements have been developed for data-processing applications. Simple space-charge and deflection-defocusing considerations indicate that in order to obtain maximum current output, the tube should be as small as possible. However, mechanical considerations and the finite size of the beam crossover limit the amount of reduction. Aluminum targets are evaporated directly on the ground surface of the multielement header. The 100-element tube is 2 1/4 inches in diameter, 9 inches long, and provides a maximum target current of 3.0 ma at a modest 2-kv accelerating potential with reasonable deflection sensitivity. The 256-element tube has the same diameter, is 11 inches long, and provides 0.75 ma of output current at 2 kv.