Electrons have made their way around the new Advanced Photon Source (APS) storage ring for the first time, a major milestone in the process of bringing the newly upgraded APS into operation. 

On April 13, 2024, members of the Accelerator Systems Division (ASD) injected an electron bunch into the new storage ring and confirmed that it traveled the full circumference. Electron bunches injected today, April 14, 2024, have now circulated more than a dozen times. This is not only a first, but an important step for the new machine, as the smallest obstruction, misalignment or power supply oscillation (for example) can affect the trajectory of an electron beam. With such a low-emittance beam, even miniscule changes such as these would be detrimental.

“Circulating beam around the storage ring is a major accomplishment, and the entire team – construction and commissioning – should be proud of the work done to get us to this point,” said Jim Kerby, director of the APS Upgrade project.

“This initial result is a testament to the work of hundreds of people both at Argonne and literally around the globe over the decade,” Kerby said. “We’re very pleased the commissioning team under the leadership of Vadim Sajaev has achieved this milestone and look forward to their continued efforts to safely commission and fully understand the new machine.”

Commissioning of the new storage ring will continue for much of the next two months, as the ASD team works toward storing beam in the ring and bringing the accelerator up to operational levels.

Once storage ring commissioning is complete, beamlines will be able to begin commissioning with photon beams, moving the upgraded APS one step closer to returning to scientific operations.