SSC Linac Beam Position Monitor System

The Superconducting Super Collider (SSC), Linac Beam Position Monitor System is designed to measure beam position and phase. Forty-three monitors will be installed in the Linac and Transfer Line. The position measurement provides information on the transverse beam position in the beam pipe with respect to a mechanical reference. The phase measurement provides information on the difference between the longitudinal phase of the beam and the radio frequency reference signal (rf reference), to be used for phase scanning and time of flight measurement. The system design and the prototypes are complete, and the series is under fabrication. The signals to be processed are extracted from four striplines, down-converted to a convenient intermediate frequency and fed into position and phase electronics. The position electronics is realized with the log-ratio technique, and the phase electronics uses a new digital technique that overcomes most of the problems of existing systems. Both position and phase analog electronics are mounted on identical VXI motherboards, containing analog-to-digital converters (ADC's) and digital circuitry