Lawrence Berkeley National Laboratory (Berkeley Lab) has selected James (Jim) Strait, a Fermilab physicist with a long history of managing large international scientific projects, to serve as the Project Director of the next-generation experiment Cosmic Microwave Background Stage 4, also known as CMB-S4. His new role is effective on July 11. The announcement follows an international search.

Strait will take on the project leadership role in CMB-S4, which is the largest collaborative undertaking yet to explore the relic light emitted by the infant universe. The experiment comprises 121 institutions from 16 countries. Among Strait’s many previous managerial positions, he served as the project director of the Long-Baseline Neutrino Experiment, program leader for the US Large Hadron Collider Accelerator Research Program (LARP), and the project manager for the US LHC Accelerator Project. He is currently a Fermilab Distinguished Scientist, where he has worked since 1985.

“I am thrilled that Jim has agreed to serve as a CMB-S4 Project Director.  This is a challenging project, both technically and programmatically, and Jim’s experience in successfully leading large projects has prepared him well to take on this important role,” said Natalie Roe, the Associate Laboratory Director for Berkeley Lab’s Physical Sciences Area.

With 21 telescopes at the South Pole and in the Chilean Atacama desert surveying the sky with over 500,000 cryogenically-cooled superconducting detectors for seven years, CMB-S4 will deliver transformative discoveries in fundamental physics, cosmology, astrophysics, and astronomy. CMB-S4 is supported by the Department of Energy’s Office of Science and the National Science Foundation. In 2020, DOE selected Berkeley Lab to lead the partnership of national labs, universities, and other institutions that will carry out the DOE roles and responsibilities for the effort.

As Project Director, Strait will be responsible for establishing the project baseline and managing the project to deliver the technical scope within budget and schedule constraints. He will work with the large CMB-S4 collaboration of scientists to ensure that the project meets its ambitious scientific goals, while also adhering to the funding agencies’ expectations for the successful management of large projects.

“CMB-S4 is a fantastic experiment that will address some of the most exciting and fundamental questions in cosmology, astrophysics, and particle physics. It is an honor to be given the opportunity to work with the CMB-S4 Collaboration and the Berkeley Lab-based project team to make this experiment a reality,” said Strait.

Strait has also served as head of Fermilab’s Particle Physics Division, where he was responsible for an organization of more than 400 people that hosted the lab’s experimental and theoretical particle physics and astroparticle physics programs. He has also played instrumental roles in the Compact Muon Solenoid (CMS) upgrade project, which is one of two large general purpose experiments at the Large Hadron Colliders. He received his Ph.D. in physics from Harvard University, and he is a fellow of the American Physical Society.

CMB-S4 is the first experiment to access the entire scope of ground-based CMB science. It will measure ever-so-slight variations in the temperature and polarization, or directionality, of microwave light across most of the sky, to probe for ripples in space-time associated with a rapid expansion at the start of the universe known as inflation.

CMB-S4 will also help to measure the mass of the neutrino; map the growth of matter clustering over time in the universe; shed new light on mysterious dark matter, which makes up most of the universe’s matter but hasn’t yet been directly observed, and dark energy, which is driving an accelerating expansion of the universe; and aid in the detection and study of powerful space phenomena like gamma-ray bursts and jet-emitting blazars.


Founded in 1931 on the belief that the biggest scientific challenges are best addressed by teams, Lawrence Berkeley National Laboratory and its scientists have been recognized with 14 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environmental solutions, create useful new materials, advance the frontiers of computing, and probe the mysteries of life, matter, and the universe. Scientists from around the world rely on the Lab’s facilities for their own discovery science. Berkeley Lab is a multiprogram national laboratory, managed by the University of California for the U.S. Department of Energy’s Office of Science.

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