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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.


August 24, 2022


Argonne has received new guidance from the U.S. Department of Energy (DOE) in response to streamlined recommendations from the Center for Disease Control and Prevention (CDC). This new guidance emphasizes personal choice and personal responsibility.

Argonne has updated its COVID-19 safety plan to align with this guidance. The laboratory and the Argonne Tandem Linac Accelerator System (ATLAS) are revising COVID restrictions and minimizing our need to adjust safety protocols when the CDC changes COVID-19 community transmission levels for DuPage County (the county in Illinois where Argonne is located).

The requirements that shift based on community levels are indicated below. All changes are effective Wednesday, August 24, 2022. 

Tied to COVID-19 Community Levels: 

  • Face Coverings: High-quality face coverings from our approved options will be optional on site when the COVID-19 Community Level is low (green) or medium (yellow); they will be required when it is high (orange). 
  • Fans and Heaters: When the COVID-19 Community Level is high (orange), restrictions on placement and the direction of the airflow in shared spaces apply. 

Not tied to COVID-19 Community Levels: 

  • Access Requirements for Visitors: Vendors, facility users, and other guests are no longer required to provide proof of vaccination or negative COVID-19 test results to enter an Argonne site. 
  • Contact Tracing: We will only perform complete contact tracing at the discretion of Argonne Health and Employee Wellness if there are signs of a cluster of cases on site. 
  • Close Contacts: People who are exposed to the coronavirus through a close contact will not need to quarantine. They will need to wear a face covering for 10 days and complete COVID-19 testing five days after exposure. 
  • Isolation of Infectious People: Users should adhere to the latest CDC guidance for COVID-19 quarantine and isolation periods.  
  • Meeting Maximums: There are no limits to the number of people who may attend a meeting in person. However, events should be planned so that attendees can be encouraged to maintain distance from others and avoid crowding. 
  • Proximity Devices: We are discontinuing the wearable proximity device program.
  • Social Distancing: Social distancing will be optional on site, no matter the COVID-19 Community Level. 
  • Testing Programs: We are discontinuing our screening program.

REMEMBER:  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 you become ill while at Argonne, stay away from others and immediately call the COVID-19 Question Line at 630-252-2555 for guidance on isolation and restriction requirements.


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.