Successful Demonstration of iGp/FBE at BEPC-II

During the first week of November, Dimtel, Inc. bunch-by-bunch feedback solution was demonstrated at BEPC-II collider in Beijing, China. Baseband signal processor iGp-396F and FBE-500L RF front/back-end were used for the demonstration.

First test was performed in the vertical plane of the positron ring. FBE-500L front-end was used in the amplitude detector mode and connected to the ΔY output of the hybrid network. iGp-396F output was applied to the power amplifiers driving vertical striplines. The top snapshot of the beam spectrum plot on the right shows beam motion measured by the system with the feedback turned off. In the averaged beam spectrum we see a large line at the vertical betatron frequency around 489 kHz.

When the feedback is turned on we see that the betatron line is completely suppressed and the RMS of the beam motion is reduced. However there is a significant signal observed at the synchrotron frequency.