Development of a solid state thyratron replacement for the LCLS klystron modulator

This paper discusses the development of a solid state replacement for the L-4888 thyratron, which is presently used in the eighty-three high-power klystron modulators of SLAC's Linac Coherent Light Source (LCLS). The motivations are to improve modulator performance, increase availability and decrease operational costs. The solid state switch is based on an array of SGTO thyristors. The challenging dI/dt (10 kA/μs), peak power (150 MW), and average power (100 kW) requirements of this application differentiate this work from prior solid state thyratron replacement efforts. Herein, are described the application (including system specifications), the present development status (demonstrated performance and reliability), as well as future development plans.