Thyratron stability improvements of SNS extraction kicker system

The Spallation Neutron Source (SNS) extraction kicker system is a high power 60Hz pulsed system used to eject a proton beam from the accumulator ring and transfer it to the mercury target. The system consists of 14 Blumlein pulse forming network (PFN) modulators that require precise timing synchronization and fast rise times. Timing jitter can result in a modulator potentially firing outside of the ideal extraction time and causing excessive beam loss. A commercial thyratron is used as the high voltage switching element in the PFN. Adjustments to the reservoir and filament heater power are used to stabilize firing times as the thyratron ages but this can reduce the lifetime of the thyratrons that are used to switch the PFN. This paper discusses the thyratron system itself, focusing on the control of the filaments and reservoir heater power sources to eliminate line sync issues and further stabilize the grid to extend lifetime in new and aging thyratrons and the results of the improvements made.