Thyratron replacement for the spallation neutron source linac extraction kicker PFN system

Abstract

The Spallation Neutron Source (SNS) extraction kicker system is a high power 60 hertz pulsed power system. [1] The system consists of fourteen identical modulators, each driving a magnet to extract a proton beam from the accumulator ring through the beam transfer line to the target. Each modulator is a Blumlein Pulse Forming Network (PFN) with a fast high current switching thyratron and low inductance capacitor banks. The thyratron switches have relatively short life times, high replacement cost, long lead-time and require routine adjustments to maintain low timing jitter and drift. [2] A solid-state thyristor based high voltage switch has been developed as a direct replacement for the thyratron. [3] This paper describes the configuration, test stand and production kicker performance of the thyristor and PFN. In addition, the development of a magnetic switch to decrease magnet current rise time is discussed.