HIGH-SPEED GATED CAMERA OBSERVATIONS OF TRANSVERSE BEAM SIZE ALONG BUNCH TRAIN AT THE KEKB B-FACTORY

In order to investigate the single-beam vertical beam-size blow-up observed(1) in the KEKB 3.5 GeV positron ring (LER), we performed beam-size observations using a high- speed gated camera capable of recording the image of a single bunch in the ring. Using this technique, we mea- sured the beam-size dependence on bunch position along a train, and studied the onset of blow-up under various condi- tions and fill patterns. The method and results are described herein.