Closed Orbit Control System for Main Ring of KEK-PS

Closed orbit deviations of the main ring of KEK-PS are corrected at injection by supplying individual currents to 56 steering dipoles placed downstream of quadrupole magnets. Half of them are used for the correction of the horizontal orbit and the rest for the vertical orbit. Correction is made by making a local closed orbit with three successive dipoles to negate the reading of the position monitor. With this system, the same procedures are repeated for all position monitors distributed around the main ring under the manual operation mode. The system also furnishes the online correction using the accelerator control computer by taking the beam position data into it.