A solution to the problem of spontaneous deflection of the beam in TWT's with low helix voltage

The spontaneous deflection of the beam in low voltage, typically low noise, traveling-wave tubes has been studied and attributed to the accumulation of stray charges on the glazed helix rods. A means of measuring the tendency of the helix to show these charging effects will be described. A method of processing of the complete helix which prevents the accumulation of charges but does not seriously affect its cold loss or other microwave properties will be reviewed. Traveling-wave tubes that have been made with helices processed by this technique cannot be made to show charging effects or beam deflections. Six tubes have accumulated 22,000 tube hours with no failures.