Storage Ring Commissioning on Schedule

Commissioning of the APS storage ring is well along and on schedule for early operations later this year. Machine studies have progressed with electrons, with the changeover to positrons expected sometime this summer. Injection is now routine, and beam lifetimes consistently exceed six hours. Low-intensity beam studies have been extremely successful, with high-current operation scheduled for upcoming machine runs.

The month of March was an intense period for those of us involved in commissioning, as the manifold problems associated with turning on a new machine were overcome one at a time. We were fortunate that most of the beam diagnostics systems worked as designed from the very start. Several weeks were spent performing measurements with less than one turn, and the single-turn capability of the beam-position monitor system was invaluable in this effort. Beam studies during the first three months of 1995 extended from evenings through the early hours of the morning. This allowed problems found overnight to be remedied during the day.

The month of April saw very significant progress in storage-ring commissioning, with the first extended availability of beam time to x-ray experimenters on beamline 1-BM. The storage ring's x-ray source size and angular divergence were measured, and information was also obtained on bunch-time structure and purity. Early indications are that the natural emittance of the ring is close to the theoretically expected value.

Conversion to day operation in the storage ring was accomplished during the latter half of a two-week run in May. High-current studies are under way, and on June 21 a single-bunch current of 5 mA was stored in the storage ring. This is the Conceptual Design Report's target value for a single-bunch current.

-G. Decker, Accelerator Systems Division

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