Observation of coherent instability in the CERN PS Booster

At high intensities and at certain working points, an instability develops in the CERN PS Booster and large coherent transverse oscillations and beam loss occur [1]. The coherent oscillations and beam loss can be effectively controlled with the transverse damper system, but the origin of the instability is not well understood. In preparation for nonlinear optics measurements in the PS Booster that will take place after CERN’s first Long Shutdown, trial measurements were made with the PSB’s new trajectory measurement system. The measurements gave some new insight into the nature of this transverse instability, and these observations are presented here.