Choreographing the Accelerator and NuMI Upgrade

The Accelerator Division recently installed these two radio-frequency cavities in the Main Injector tunnel as part of Fermilab’s Accelerator and NuMI Upgrade. Photo: Marty Murphy, AD

More than a year ago, Fermilab Engineering Physicist Cons Gattuso hung in his Cross Gallery office a large pin board covered with notes and strung with ribbons of different colors. The many-colored diagram, with its numerous and moveable parts, laid out the grand and dynamic plan for completing Fermilab’s Accelerator and NuMI Upgrade.

The plan’s elaborateness is evident in the numbers. Since the beginning of the shutdown in April 2012, more than 300 employees—roughly 18 percent of the laboratory’s workforce—have contributed directly to the upgrade. Together, they have pulled 1 million feet of cable, handled more than 450 tons of material, reworked 1,500 feet of the new transfer line section and modified 10 percent of the vacuum system.

Led by members of the Accelerator Division, engineers and technicians from across the laboratory have been working for the last 13 months to prepare Fermilab’s Main Injector accelerator, the Recycler storage ring and the NuMI beamline to deliver proton beams of higher power than previously obtained. They have also been upgrading the NuMI target to handle the higher-intensity beams used for the NOvA experiment. These upgrades are an essential part of the laboratory’s shift to focus on Intensity Frontier research programs.

In a few weeks, the upgrade will be complete. It has been a project of complex choreography—hence the ribbon board, where each ribbon represents a crew’s workflow.

“If you are completing a major upgrade to a complex of this size, you can’t keep it internal to the Accelerator Division,” Gattuso said. “You pull resources from across the lab.”

Previously, the Main Injector required 2.2 seconds to load, manipulate and extract the beam delivered from the Booster. With the upgrade, the Recycler, which used to store antiprotons for transfer into the Tevatron, will now serve as a staging area for the beam, taking care of the prep work that the Main Injector used to be responsible for. Now freed of those duties, the Main Injector will spend almost no time idling, and the turnaround time will be slashed from 2.2 to 1.3 seconds—more than one-and-a-half times faster.

“It’s a way of recycling the Recycler,” Gattuso said.

To repurpose the Recycler, upgrade teams gutted sections of the machine and installed new beamlines. They also installed new radio-frequency power systems, including two new accelerator cavities fabricated at the laboratory. The upgrade also required software and programming support.

After all is said and done, the upgraded Fermilab accelerator complex will deliver proton beams with a peak power of 700 kilowatts—double the previous peak power of 350 kilowatts—which is what’s needed to produce the large number of neutrinos needed for the NOvA experiment.

“We’ve been good at keeping this choreographed chain going,” said Upgrade Associate Project Manager Paul Derwent. “That’s really due to people overseeing the day-to-day installation and how well they work together. We had great help and support from people from the Technical and Particle Physics divisions. We needed more people than only those in the Accelerator Division.”

AD plans to turn on the upgraded accelerator complex and begin sending beam through the Main Injector and Recycler later this month. The moment that beam comes on will be a welcome one.

“I look forward to being back in operations, not just installation and project, but actually operating the Recycler and Main Injector again,” Derwent said.

For Fermilab, it will be the beginning of a new era of research.

Leah Hesla