Vertical Beam Size Measurement by Streak Camera Under Colliding and Single Beam Conditions in KEKB

Beam behaviour of KEKB was studied by measurement of the beam size using a streak camera. The effects of electron-clouds and beam-beam interactions on the vertical beam size were examined in beam collision. We injected a test bunch of positrons 2 RF buckets after a bunch to enhance the electron cloud effect and changed electron beam conditions to see the beam-beam effect. The beam size was also measured in a single positron beam condition and compared with that during collision. The result of the measurement is reported in this paper.