Reliability improvements for Cockroft-Walton high voltage multipliers

Persistent equipment failures with 50 kV Cockroft-Walton (CW) high-voltage multiplier modules have resulted in a two-year reliability improvement program to reduce downtime from failed multipliers. A complete analysis of the reliability problem was performed. Failure modes were identified, stringent component testing implemented, epoxy potting procedures studied, modifications to internal structures implemented, and lengthy burn-in testing performed on modified multipliers. Internal corona (due to nonuniform electric field intensities) and tracking (from possible internal contamination) leading to eventual multiplier failure were addressed as significant causes of multiplier failures. Modified multipliers are shown to have greatly increased reliability, leading to corresponding decreases in maintenance manpower requirements.<>