Observation of transverse quadrupolar tune shifts in the Photon Factory storage ring

The frequencies (tunes) of transverse quadrupolar oscillations were measured in the 2.5-GeV Photon Factory storage ring at the High Energy Accelerator Research Organization (KEK). As a result, remarkable shifts in the quadrupolar frequencies with the bunch current were found; they were both positive and negative in the horizontal and vertical directions, respectively. This result can be explained by a focusing effect due to short-range wakefields containing a quadrupolar component

Beam injection with a pulsed sextupole magnet in an electron storage ring

We have developed a new beam injection system with a single pulsed sextupole magnet (PSM) at the photon factory storage ring (PF ring) in the High Energy Accelerator Research Organization. We demonstrated beam injection with this system and succeeded in storing a beam current of 450 mA, which is the normal operating beam current of the PF ring. Top-up injection was also achieved. Coherent dipole oscillation of the stored beam and fluctuation of photon intensity observed at synchrotron radiation beam lines during the PSM injection became very small compared with a pulsed bump injection system that is normally used in the beam injection at the PF ring. This experiment is the first demonstration of beam injection using the PSM in an electron storage ring