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Argonne Tandem Linac Accelerator System

The prime national facility for nuclear structure research. The Argonne Tandem Linac Accelerator System (ATLAS) is the world’s first superconducting linear accelerator for heavy ions at energies in the vicinity of the Coulomb barrier.



On February 25, 2022, the U.S. Centers for Disease Control and Prevention (CDC) issued new COVID-19 safety recommendations centered on COVID-19 Community Levels, which assess the risk the coronavirus poses using county-level data. Argonne has worked with the Department of Energy Argonne Site Office to updated our COVID-19 safety plan accordingly, outlining protocols for the low, medium, and high Community Levels.

Under the new guidance, Argonne’s Lemont campus is linked to the COVID-19 Community Level of its home county, DuPage, which is currently categorized as low. Therefore, we are updating our COVID-19 controls, effective Monday, March 14, 2022, and until our COVID-19 Community Level should change. The following updates apply to users of the Argonne Tandem Linac Accelerator System (ATLAS).

  • Face coverings are no longer required, regardless of vaccination status, except in the Health and Employee Wellness (HEW) clinic and in small, enclosed spaces when it is not possible to maintain a distance of at least 3 feet from others (such as elevators and government vehicles).
  • Social distancing is optional, regardless of vaccination status.
  • The wearable proximity device program is suspended. If you currently have a device, contact the ATLAS User Office at atlas-​admin@​anl.​gov for information about how to return it.

COVID-19 controls that remain in place include:

  • Site-access requirements for users of ATLAS remain in place: users must provide proof of vaccination or a negative result from a COVID-19 test conducted within 72 hours of site access.
  • Users should not come to Argonne or ATLAS if they are not feeling well or exhibit symptoms consistent with COVID-19, regardless of vaccination status. If users become ill while at Argonne, they should stay away from others and immediately call the COVID-19 Question Line at 630-252-2555 for guidance on isolation and restriction requirements.
  • Gatherings remain limited to 50 or fewer people.
  • The lab will sustain augmented flow and filtration for building ventilation, enhanced surface cleaning and disinfection, and its contact tracing program.

Please note that the most common protections people can apply—booster shots, face coverings, and social distancing—are now a matter of personal choice. Please respect and support our colleagues no matter which choices make them most comfortable.

Our lessened restrictions reflect the rapid and sustained decrease in COVID-19 cases locally following the Omicron variant surge in January. Whenever the COVID-19 Community Level changes for DuPage County, our protocols will also change.

If you have additional questions, please contact the ATLAS User Office at atlas-​admin@​anl.​gov.


This is the energy domain best suited to study the properties of the nucleus, the core of matter and the fuel of stars. ATLAS can provide beams of essentially all stable isotopes from protons to uranium, and a variety of light radioactive beams through our in-flight production program and heavier neutron-rich isotopes from CARIBU.

ATLAS is a U.S. Department of Energy User Facility that hosts roughly 200 to 300 users each year. It is supported by the Office of Nuclear Physics of the Department of EnergyATLAS users come from U.S. universities and national laboratories as well as from foreign institutions. The facility is also accessible to industrial users. 


With an unwavering focus on our mission, our researchers take an interdisciplinary approach to research, advancing their fields of study and generating new knowledge for the benefit of future generations.