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A description is given of the design and testing of a directly heated, stable, electron source utilizing a single‐crystal lanthanum hexaboride (LaB6) cathode. The emitter mounting fixture consists of an adjustable molybdenum base unit supported on gas‐impervious alumina or machinable glass. Single‐crystal cathode rods are securely clamped and positioned between vitreous carbon jaws that are resistively heated. The complete assembly is designed to be a direct ’’plug‐in’’ substitute for the conventional tungsten thermionic filaments used in electron‐beam instruments. The cathode current density for 〈110〉 axial orientations is found to be ten times higher than that for 〈100〉 orientations under equivalent conditions, a value of 50 A cm−2 being measured at 1500°C with an observed lifetime in excess of 300 h. Optimum vacuum conditions for high lifetime and stable operation are in the range 1×10−6 Torr and lower. Comparison values for the emission at various temperatures from other borides, and tungsten, are als...

135 nsec pulses ofλ = 1.06μm light from a Nd: YAG laser have been used to form Schottky barriers by irradiation of a 500A thick metal film on n-type silicon. Large area barriers were fabricated by over-lapping individual 30μ diameter laser pulses of from 4 to 12 J/cm2. The barrier height was 0.73 ± 0.03 V, independent of the laser power. The barrier quality, as assessed by measurement of the forward current characteristic, decreased with laser power to a value of n = 1.5 at 12 J/cm2.

Measurement of thermionic electron emission values for pointed LaB6 single‐crystal emitter cathodes has shown that 〈110〉 axial orientations yield emission values ten times higher than 〈100〉 orientations at 1545 °K. Minimum values were obtained for the 〈510〉 directions. These findings seem encouraging in achieving perhaps two orders of magnitude higher emission fluxes as compared to tungsten emitters.