Gallium arsenide digital integrated circuits for controlling SLAC CW-RF systems

In order to fill the PEP and SPEAR storage rings with beams from the SLC (Stanford Linear Collider) linac and damping rings, precise control of the linac subharmonic buncher and the damping ring RF is required. Resettable GaAs master/slave D-type flip-flops have recently been developed which are capable of operating at frequencies of 3 GHz and higher. Using these digital devices as frequency dividers, one can phase-shift the SLAC (Stanford Linear Accelerator Center) continuous-wave (CW) RF systems to optimize the timing for filling the storage rings. The performance of integrated circuits from two vendors was evaluated for this application. Using microstrip circuit techniques, the authors built and operated in the accelerator several chassis to synchronize a reset signal from the storage rings to the SLAC 2.856-GHz RF and to phase-shift divide-by-four and divide-by-sixteen frequency dividers to the nearest 350-ps bucket required for filling.<
>