Trigger control system with beam gate at SuperKEKB injector linac and damping ring

Accelerator control system is indispensable for the beam handling. Especially, a timing control is much important tool for SuperKEKB project. In the SuperKEKB project, the timing control system became more complex than previous KEKB project, because a Damping Ring (DR) was newly constructed. The DR is located at the middle of injector Linac. Positron beam is delivered from Linac to DR at the energy of 1.1 GeV, and is made lower emittance there. After being stored during 40 ms, the positron beam is returned to Linac. To control the beam injection and extraction at DR, we made two different timing at main timing system. In the DR, it is necessary to control the timing in the various situation, storage mode that is only injection, extraction only mode after optics measurement and so on. To satisfy this situation, "Beam Gate" handling system was embedded in the timing system. We also adopted beam gate handling at injector Linac. This system is very useful not only machine inhibit control but also identification the beam is transported or not. (author)