BATAVIA – The U.S. Department of Energy formally approved Fermi National Accelerator Laboratory in Batavia to proceed with its design of PIP-II, an accelerator upgrade project that will provide increased beam power to generate an unprecedented stream of neutrinos.

The subatomic particles could unlock humans' understanding of the universe and enable a broad program of physics research for many years to come, a news release stated.

The PIP-II acronym stands for Proton Improvement Plan II. The accelerator upgrades are integral to the Fermilab-hosted Deep Underground Neutrino Experiment, also known as DUNE, which is the largest international science experiment ever conducted on U.S. soil.

DUNE requires enormous quantities of neutrinos to study the mysterious particle and, with the latest approval for PIP-II, Fermilab is positioned to be the world leader in accelerator-based neutrino research. The Long-Baseline Neutrino Facility, which also will support DUNE, had its groundbreaking ceremony in July 2017.

PIP-II is the first accelerator project in the U.S. that will have significant contributions from international partners, including institutions in India, Italy, France and the United Kingdom. The Department of Energy's Argonne and Lawrence Berkeley national laboratories are also major participants.

"We think of PIP-II as the heart of Fermilab: a platform that provides multiple capabilities and enables broad scientific programs, including the most powerful accelerator-based neutrino source in the world," Fermilab PIP-II Project Director Lia Merminga stated in the release. "With the go-ahead to refine our blueprint, we can focus designing the PIP-II accelerator complex to be as powerful and flexible as it can possibly be."

The largest and most ambitious of these detectors are those in DUNE, which is scheduled to start up in the mid-2020s. DUNE will use two detectors separated by a distance of 800 miles – one at Fermilab and a second, much larger detector situated 1 mile underground in South Dakota at the Sanford Underground Research Facility.

The centerpiece of the PIP-II project is the construction of a new superconducting radio-frequency linear accelerator, which will become the initial stage of the upgraded Fermilab accelerator chain. It will replace the current Fermilab Linac – or linear accelerator, in which the particle beam proceeds along a straight path. The plan is to install the SRF linac under 25 feet of dirt in the infield of the now decommissioned Tevatron ring.

Fermilab expects to complete the project by the mid-2020s, in time for the start-up of LBNF/DUNE.

For more detail on the project and science involved, visit fnal.gov.