Single And Multi-gap Thyratrons In Inverse Diode Mode

To satisfy ever higher kick strength requirements in reduced space, present and future fast kicker magnets in particle accelerators must often be of short-circuited delay line type, despite the full voltage reflection produced. Three EEV ceramic thyratrons, types CX 1154 (single-gap), CX 1168 (double-gap) and CX 1171 (triple gap) have been tested in inverse diode mode in a cable PFN pulse generator to absorb these reflections. The single-gap tube operated without difficulty if triggered prior to the reflection arrival. The refusal voltage was then limited to 2 kV during a few tens of nanoseconds. The double and triple-gap tubes required an extra R-C arrangement on their gaps closest to the anode to operate as inverse diodes. They then exhibited low refusal voltage (respectively 4.kV and 6 kV during some 30 ns) but only when the operating voltage was higher than 35 W. Pre-triggering had no beneficial effect. These results are discussed in terms of their acceptability for the different kicker magnet applications encountered in present-day synchrotron complexes.