Switching system for the FXR accelerator

A switching system has been designed for a 20 MeV flash x-ray linear induction accelerator which is being built at Lawrence Livermore Laboratory. The switching system fans out a single command pulse and amplifies it to obtain the voltage necessary for reliable, low-jitter triggering of the accelerator components. This system consists of two major subsystems: (1) the Blumlein Charging Subsystem which first triggers thirteen Marx generators, and then charges 54 water-filled Blumleins, and (2) the Blumlein Triggering Subsystem which triggers the already-charged Blumleins to produce a 90 nanosecond, 400 kV pulse in each of 54 ferrite-loaded accelerator modules. The first subsystem consists of charged high voltage cabling with two parallel switch gaps either of which will trigger the Marx generators. The major components of the second subsystem are three stages of switch gaps along with the necessary high voltage cabling. Two parallel first stage switch gaps trigger thirteen second stage gaps, which in turn trigger 54 third stage Blumlein switch gaps synchronous with the passage of the electron beam pulse. These spark gaps are operated at a voltage of 150 to 350 kV with a 1/3 hertz repetition rate. Varying the cable lengths creates the actual delay times in the triggering of each component. Redundancy is built into the system to insure the high reliability which is essential for the flash radiography application