Experimental observations of pulse shortening in a linear-accelerator waveguide

This paper describes experimental observations made of the parasitic oscillations which can occur in electron linear accelerators and which cause the phenomenon known as pulse shortening. Measurements have been made of the frequency of oscillation, the noise level from which the wave builds up, the rate at which it builds up and the maximum power levels achieved. The presence of resonant conditions was noted during the buildup process. Appendixes give details of an approximate theory of the mechanisms of oscillation.