TUNE MEASUREMENT OF SRRC BOOSTER DURING RAMPING

The setup for tune measurement of Synchrotron Radiation Research Center (SRRC) booster and its performance are described in this report. Tune drift during ramping was observed in routine operation. The fractional tune drift can be as large as 0.2. In some of the cases, beam capture at injection and its acceleration was severely degraded. In order to improve this situation, a measurement system was set up to monitor tune shift during ramping. Tune information was obtained by using FFT conversion of turn by turn beam position signals. Besides, tracking errors among focusing/defocusing quadrupoles and dipole were monitored with precision magnetic current meters. Their ratio varied during ramping was correlated to the tune shift mentioned above. With the help of these two monitoring tools, the working tunes were optimized to get more efficient operation.