The ELETTRA gun trigger module

The ELETTRA injector is a full energy linear accelerator (linac). Most of the triggers for the timing system are generated by a module named the gun trigger module. The gun is triggered in synchronism with a reference bucket of the storage ring. It can be programmed with a delay between 2 and 684ns, a range which covers one revolution period of the storage ring, so that any arbitrary bucket of the ring can be filled. The module also generates the gun trigger for working in FEL (free-electron laser) mode, which needs a repetition of from 30 to 50 ns in a 10 mu s window. The jitter of all these triggers is less than 50 ps. The gun trigger module was developed in the VMEbus standard, using transistor-transistor logic and emitter-coupled logic technology. It is remotely programmable through the ELETTRA control system. The general architecture of the ELETTRA timing system is also described.<>