Accelerator and NuMI upgrades for NOvA

Paul Derwent

Paul Derwent, the associate project manager for the NOνA experiment, wrote this week’s column.

Fermilab’s proton beam will turn off on Monday, April 30, for 11 months, so that we can upgrade our infrastructure in preparation for our next steps into the Intensity Frontier, with NOvA.

The NOvA experiment is a second-generation neutrino mixing experiment. Neutrinos exist as three different types, and NOvA researchers will look at the rates that neutrinos shift between those types. If the rate differs between neutrinos and antineutrinos, it could explain why there’s more matter than antimatter in the universe.

Like most neutrino experiments, NOvA will request a lot of protons. To meet the experimenters’ scientific goals in six years, the Accelerator Division has to double the current capabilities of the accelerator complex. To increase the total protons on target, there are two options: increase the intensity per pulse or increase the frequency of pulses. We will do both.

In current operations, protons from the Booster are injected and accumulated in the Main Injector. In the Main Injector, the energy of the protons is increased by a factor of 15 and sent to the neutrino production target. In the future, protons will accumulate in the Recycler, increasing the frequency of the pulses to the target by 55 percent. With improved technical components, the pulse intensity is increased by 30 percent. The combination of increased frequency and increased intensity doubles the performance.

The Accelerator and NuMI upgrades for NOvA started six years ago. From conceptual designs, the project has advanced through many reviews, procurement and fabrication to be ready for the upgrades. It is a significant change in operations, requiring a significant access period to the accelerator tunnels.

During the shutdown, we will install the hardware to make this operational change. This hardware will include new transfer lines from the Booster to the Recycler and from the Recycler to the Main Injector, as well as additional radio-frequency hardware in both the Recycler and the Main Injector. The NuMI target hall will also have significant upgrades to handle the higher pulse intensity and frequency. There will be about 40 technicians, from AD, PPD and TD, working full time on the upgrades for the next year.

At the end of this long shutdown, AD will be prepared to deliver the desired protons per year to the NOvA experiment, opening up new windows on the understanding of neutrino mixing.