SENSITIVITY AND FREQUENCY RESOLUTION OF A CYCLOTRON RESONANCE MICROWAVE DETECTOR

摘要

Continuing research on the utilization of cyclotron resonance in low voltage beams for the selection and detection of microwave signals is reported.nAnalysis of a drifting sheet beam which exceeds critical perveance shows that greatly increased distortion of the cross-section results. This, plus the fact that each lamina of such a beam has a different cyclotron fre¬quency, explains the poor frequency resolution observed in past tubes, which are now recognized to have operated in this mode. These tubes also exhibited oscillation and noise tremendously in excess of full shot noise. It is shown analytically that shot noise undergoes amplification in certain portions of a beam beyond critical perveance. Two tubes designed to operate well below this point have exhibited noise properties in exact agreement with the minimum value theoretically to be expected. Oscillation was absent.