STUDY OF CROSSED FIELD AMPLIFIERS.
Quarterly progress rept. no. 15, 16 Dec 66-15 Mar 67,
CALIFORNIA UNIV BERKELEY ELECTRONICS RESEARCH LAB
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The work on the crossed-field potential minimum fluctuations yielded the important conclusion that cathodes must be shorter than about 0.6 of a cycloid length to avoid instabilities and, therefore, excess noise. Also simple formulae were found for the potential minimum static characteristics. The flattened helix appeared to be a good choice of circuit for a low-noise tube because of the high interaction impedance. Limitations on minimum reasonable electrode size and available power supplies prevented raising the cathode current density higher than about 0.27 amperessq cm more space-charge smoothing was achieved with higher current. It appeared to be possible to find smoother self-consistent fields and, therefore, simpler electrodes than those calculated by Rao in his initial design of the magnetically shielded crossed-field gun. Initial analytic estimates of the heat flow in a laser excited cathode were based on a one-dimensional model. They indicated that sufficient power should be obtainable from an argon laser to obtain interesting beam currents. Analysis of the interaction between drifting charge carriers and electromagnetic waves in InSb indicates that, for thin slabs, growing waves can be expected. The case of crossed magnetic field on an acoustic wave interaction in InSb is expected to lead to amplification at frequencies into the microwave range. Author
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- Solid State Physics