NOISE CHARACTERISTICS OF CONVERGENT CROSSED-FIELD SPACE-CHARGE FLOWS.
MICHIGAN UNIV ANN ARBOR ELECTRON PHYSICS LAB
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The purpose of this study is to investigate the noise transport characteristics of space-charge flows in crossed d-c electric and magnetic fields. The theoretical work consists of a Monte Carlo analysis of the noise characteristics of Kino-type electron guns, a parallel plane diode gun and a crossed-field drift space. The experimental studies are concerned with the detection and control of signal noise transport along the beams in these guns. An IBM-7090 high speed digital computer is used to simulate random electron emission from the cathode and the subsequent space-charge flows in the gun and drift regions under both short- and open-circuit assumptions. Relevant data for noise parameter calculations are collected during these simulation runs and stored on magnetic tapes. Kinetic noise-voltage and noise-current fluctuations are considered only in the direction of the d-c beam velocity at each point in the beam. A significant change in the values of the noise parameters at a given beam cross section is found to occur in the neighborhood of the hybrid frequency for that region of the beam. Space-charge smoothing is not limited to the potential minimum region but continues for some distance along the beam. An r-f probe technique was used to study signal noise transport in crossed-field guns. Self-oscillations were detected in the frequency range of 90-125 MHz and the oscillation frequency was found to be a function of electric and magnetic field strengths and cathode temperature. Author
- Electrical and Electronic Equipment
- Electricity and Magnetism