Linear theory of shot noise in harmonic gyroklystrons and gyro-TWT amplifiers

Expressions for the equivalent input power level from bare shot noise in two types of gyro-amplifiers are calculated. The analysis is limited to the small gain, ignores correlations between electrons, and is further restricted to cold beams. The fields are calculated in a self-consistent manner directly from the electron beam as a first-order perturbation. In the first case, the equivalent input noise temperature for a harmonic gyro-traveling wave tube amplifier is derived. In the second case, the noise temperature of a harmonic gyroklystron input cavity is derived. A sample calculation is given for each using the TE₀₂₁ and TE₀₂ modes with a 60-kV 1-10 A annular electron beam operating near the second harmonic of the cyclotron frequency.