Power and frequency measurements from a uniform backward wave oscillator as a function of length

Book · Sat Dec 31 04:00:00 EST 1994

OSTI ID:51768

Moreland, L D; Roitman, A M; Schamiloglu, E; Pegel, I V ^[1]; Lemke, R W ^[2]

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1. Univ. of New Mexico, Albuquerque, NM (United States)
2. Sandia National Labs., Albuquerque, NM (United States)

The authors describe results from an experiment where the number of ripple periods in the slow wave structure of a backward wave oscillator (BWO) is increased. Both microwave power and frequency measurements are made for each shot. For a given cathode voltage and beam current, the microwave peak power and frequency are plotted as a function of BWO length. In previous investigations, the observation of two power maxima as a function of length was explained by the interaction of the electron beam with the forward traveling wave and reflections at the transition from the slow wave structure into the output waveguide. However, recent numerical calculations using the phase dynamics of electron beam and electromagnetic modes suggest that the power maxima are due to the phase relationship between the electron beam density wave and the backward wave. Experiments were performed on the Sinus-6, a relativistic electron beam accelerator. By adjusting the pressure in the Sinus-6 spark gap switch, cathode voltages between 400 kV to 650 kV can be obtained. The experiment was repeated for different sets of beam parameters. In all cases, the magnetic field used for beam transport was longer than the length of the slow wave structure. The experimental results are compared with phase model calculations and PIC code simulations using KARAT and TWOQUICK.

• OSTI ID: 51768
• Report Number(s): CONF-940604--; ISBN 0-7803-2006-9
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
BACKWARD WAVE TUBES
BEAM DYNAMICS
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
EXPERIMENTAL DATA
FREQUENCY MEASUREMENT
K CODES
POWER
T CODES