SPring-8 starts its top-up operation

The top-up operation of the SPring-8 storage ring started successfully earlier in the summer this year. In the top-up operation, electron beam is injected at short intervals during user beam time, and the current stored in the storage ring is kept constant. Accelerator physicists at SPring-8 have termed their top-up operation an `ideal top-up operation' and is a culmination of six years of R&D work. Presently, the beam is injected at an interval of 1 min or 5 min in order to keep the stored current at 99 mA. The injection current for refilling is 30–40 µA. The temporal variation of the stored current is about 0.1%.