Present status and beam-stability issues of the KEKB injector linac

The KEKB injector linac was completely upgraded for the KEK B-Factory (KEKB) project in March, 1998. Many difficulties have been overcome during the elaborate commissioning of the upgraded linac since the end of 1997. The 3.5-GeV positron and 8-GeV electron beams have been injected to the KEKB rings with good performance. Much effort has also been continuing to stabilize the intensity and quality of the beams. Some experimental results on the beam stability issues am shown together with the recent operation status in this report. A beam test on a new scheme of a two-bunch injection was started in order to increase the positron intensity since March, 2001.