High beam current experiments for the KEKB conducted at the TRISTAN Accumulation Ring

Dedicated machine time of about 10 weeks has been devoted to the high beam current experiment by using an electron beam of the TRISTAN Accumulation Ring (AR). In the experiment, we investigated the performance of prototypes of RF cavity systems and a bunch-by-bunch feedback system which will be used in the KEKB. We found that the RF cavity systems work very well at beam currents of more than 500 mA. The bunch feedback system was very effective in suppressing the instability. We also made an experiment on the fast ion instability with interesting results.