(A/I) PROMPT BUNCH BY BUNCH SYNCHROTRON OSCILLATION DETECTION VIA A FAST PHASE MEASUREMENT*

An electronic system is presented which detects synchrotron oscillations of individual bunches with 4 ns separation. The system design and performance are motivated by the requirements of the proposed B Factory facility at SLAC. A comb generator is used to produce an eight cycle coherent tone burst at 3 GHz from each bunch. The phase of the coherent burst is compared with a master oscillator in a double balanced mixer. The detected mixer output is digitized at a 250 MHz rate, yielding a unique phase measurement for each bunch. Laboratory results are presented which show that the prototype is capable of measuring individual bunch phases with better than 0.5 degree resolution at the 476 MHz RF frequency. A system design for damping longitudinal oscillations of 1658 bunches using this detector is also shown