LFW: Any cool new laser tech/advances involved? What enables doubling the electron beam’s energy?
Mike Dunne: Yes, lots! The LCLS-II projectwhich was completed in 2023, used 37 superconducting RF (SRF) cryomodules to accelerate up to 1 million electron bunches per second up to 4 GeV. Since LCLS-II, there have been significant advancements in SRF technology, specifically refinement of the nitrogen doping and cavity production processes. This performance enhancement will enable LCLS-II-HE to double the accelerator energy to 8 GeV with only 23 additional cryomodules.
In addition, we need to extend the performance of the optical laser systems that drive the ultrafast events that scientists study, along with the x-ray detector systems and data processing systems and sample delivery systems. There needs to be a coordinated leap in performance across all these technologies—and an integrated controls system to drive them to operate together.
LFW: What kinds of cool quantum things can you explore?
Dunne: Quantum phenomena drive much of the natural world around us—even though we can’t usually see this in action. LCLS changes this and allows us to study how electrons and atoms interact with each other—and how subtle quantum effects can change how our bodies, our technologies, and even our planet behaves!
One example is in how we manufacture something as basic as fertilizer. It turns out that the process developed by nature to make ammonia is very efficient—it’s able to happen in ambient conditions, thanks to a molecule called nitrogenase. But we humans haven’t yet figured out how to do this—we need very high temperatures and pressures in big industrial reactors. The solution is to study nature in exquisite detail, watching the pathways that are generated by biological enzymes and how the subtle quantum response of molecular interactions create such efficient chemical processes.
Another example is the development of faster computers and communications. Our society went through a revolution in the 20th century when we built microelectronics, which use electrical charge to drive information flow. There are, in principle, much faster ways to pass information that could move us from gigahertz speeds (a billion processes per second) to terahertz (a trillion) and even petahertz rates (a million billion). These would use pulses of light or quantum phenomena such as the spin of an electron. But we need to measure these effects on their natural timescales (nanoseconds down to attoseconds)—which is only possible with ultrafast lasers such as LCLS.
LFW: Can you explain why “hard” x-rays are so cool/intriguing for science?
Dunne: Hard x-rays have a short wavelength—equivalent to the size of an individual atom—so they can be used to form very high–resolution images of complex objects, such as proteins that drive how our bodies function, or next-generation microelectronics, or the inner workings of clean energy systems such as batteries, or the production of hydrogen fuel. With LCLS, these x-rays are delivered in ultrafast bursts—short enough that we can capture the formation of chemical bonds or the transfer of energy and information across a molecule. This means we can produce stop-motion movies of how these complex systems respond in real time, and study in detail how they function to help develop new pharmaceuticals, or much faster computers, or more efficient industrial processes.
LFW: Most surprising or challenging aspects of the LCLS-II-HE upgrade?
Hays: It will be a herculean challenge to upgrade the machine starting in FY26.We’ll warm up the superconducting accelerator, add 23 additional cryomodules, a new liquid helium distribution system, upgrade the hard x-ray user facility, and return the entire facility to operations within 15 months.
Leading a 10-year mega-project has been incredibly challenging. LCLS-II-HE is a collaboration of five different national laboratories spread across the country, working together to deliver a new scientific capability to the Department of Energy.
Developing a suitable beam stop for a 200-W, hard x-ray laser has been challenging. These beams like to drill through anything in their path!
LFW: Fun fact(s) about LCLS-II-HE most people don’t already know?
