Stony Brook University and Brookhaven National Laboratory (BNL) are leading a significant upgrade to the experiment, called the U.S. ATLAS Phase I Upgrade, and have received Critical Decision-4 approval from the U.S. Department of Energy (DOE), signifying the completion of the project and a transition to operations.
“This milestone will enable us to push the boundaries of our understanding, following the discovery of the Higgs boson at CERN, which resulted in the 2013 Nobel Prize in Physics,” said Project Director Jonathan Kotcher, a senior scientist at DOE’s Brookhaven National Laboratory.
The U.S. ATLAS Phase I Upgrade is the initial stage of a larger upgrade planned for the LHC—the High Luminosity Large Hadron Collider (HL-LHC) project. The goal is to substantially increase the LHC’s luminosity, enabling scientists to collect 10 times more data from particle collisions, observe very rare processes, and make new discoveries about the building blocks of matter. But first, long-term experiments like ATLAS needed to undergo initial upgrades to prepare for the coming years before the LHC will transition to the HL-LHC mode.
“The U.S. ATLAS Phase I Upgrade involved building modern electronics to replace aging elements with more efficient ones, but it also provided the experiment with new and improved functionalities,” said Project Manager Christopher Bee, a senior scientist at Stony Brook.
Specifically, the project focused on three components of ATLAS: the trigger/data acquisition system, the liquid argon calorimeter, and the forward muon detector (known as the New Small Wheel). Combined, upgrades to these three components will provide scientists with the ability to collect data more efficiently and at higher data collection rates.
“Every second, there are several billion proton-proton collision events detected by ATLAS, but only a few hundred are recorded,” Bee said. Those events are selected by the trigger system, which sifts through a wealth of uninteresting events to find ones that may point to new physics or rare Standard Model events.
“The data acquisition system moves data from the detector through the trigger system, and then it puts the selected events onto storage for further analysis,” he said. “Upgrades to this system will improve its ability to select key events.”
Twelve U.S. universities and DOE’s Argonne National Laboratory collaborated with Brookhaven Lab and Stony Brook to complete the U.S. ATLAS Phase I Upgrade on time and under budget. This $44 million upgrade project was supported by DOE ($33 million) and the National Science Foundation (NSF) ($11 million).
“We very much appreciate the support from both DOE and NSF that has allowed us to realize our goals in helping prepare ATLAS for a bright future,” said Bee. “We look forward to capitalizing on the new scientific opportunities enabled by these upgrades.”