Accelerators

A CONVERSATION WITH CAMERON GEDDES

How do the Lab’s accelerators support the Lab’s mission?

The Laboratory’s leadership in these areas is based on the twin central legacies of E.O. Lawrence. One is the accelerators themselves; he of course invented the cyclotrons that started modern accelerator science. His other legacy—comparable to particle accelerators in its revolutionary nature and breadth of influence—is team science, which is foundational to our own workstyle and our numerous intramural and extramural partnerships, and is fundamentally necessary for the scale of much of the research we perform today. We invite you to watch the Berkeley Lab video Excellence in Accelerators to learn more about what we do, why, and how.

Particle accelerators and accelerator-based photon sources are indispensable engines of scientific discovery and are used in applications across industry, national security, and medicine. Here at Berkeley Lab, the Advanced Light Source (ALS) is a shining example. It accelerates electrons and uses precise control of electron beams to create soft x-rays to probe matter. Thousands of users a year explore materials, improve batteries, advance biosciences, and more with these x-ray beams. We are also extensively involved in designing the next-generation version of this user facility, the ALS Upgrade.

Extending the capabilities and reducing the size and cost of accelerators hold the key to several grand challenges of science, including better understanding the structure of the universe through high energy particle physics; creating brilliant photon sources for basic energy sciences and materials; and exploring new states of matter. These and related systems are also crucial to fusion energy sciences. ATAP is driving the extension of existing particle accelerators using advanced magnets, controls, simulations, and beam physics. For example, new high-field magnets are being used to upgrade the Large Hadron Collider in its search for new particles, as well as in compact fusion-energy concepts.

At the same time, we are creating new compact accelerator technologies and the lasers that drive them, with the potential to greatly extend the reach of fundamental science and also to make the advanced capabilities developed in leading-edge large scientific facilities such as the Advanced Light Source available to applications from medicine to security. For example, advanced laser-driven accelerators may form the basis for the next generation of very high-energy colliders. In addition, making high-performance accelerators compact enough to fit in a clinic or factory could support improved cancer detection and treatment, precision nondestructive measurements required for advanced manufacturing and nuclear security, and environmental carbon sensing for understanding global climate.

What are the top 3 or 4 areas of interest or areas of growth for the accelerators today?

The top drivers for the next generation of accelerators include: enabling new advances in fundamental physics; advancing medical and security measurements and treatments; creating clean fusion energy; and enabling tools for a carbon economy and quantum information science. Developing the required performance requires drawing on a wide variety of technologies and areas of scientific research. The Laboratory is uniquely positioned to do this through our interlinked programs in superconducting magnets and advanced precision controls that are the key to next-generation accelerators and fusion devices, laser-driven particle accelerators that offer transformative compactness and the lasers that drive them, accelerator physics for light sources (including ALS and ALS-U) and particle colliders, and accelerator and fusion applications. Computing is a vital tool throughout, and we both use and advance the state of the art in high-performance simulations and tools leading the push toward the exascale, and apply artificial intelligence and machine learning feedback concepts that enable understanding and control of the complexity required for high performance. Key directions include:

• Extending the capabilities of accelerators for high energy particle physics at the energy and intensity frontiers, as well as next-generation photon sources. New high strength magnets are extending the reach of discovery at machines like the Large Hadron Collider that probe fundamental particle physics and expand our understanding of the basic physical laws that are at the root of the physical sciences. Feedback controls (including AI/ML) and advanced simulations allow us to better understand and control complex systems, extending performance both for photon sources like ALS-U and for colliders.

• Pioneering a new generation of radically more compact accelerators, which achieve in centimeters what takes current technologies hundreds of meters. Using intense lasers to drive waves in ionized plasma, we circumvent the limits on how much acceleration present-day machines, based on radiofrequency power in resonant metallic cavities, can impart to particles. This has the potential to enable much higher energy systems at a physically and financially practical size, extending the reach of basic science in understanding fundamental physical laws and the structure of the universe through high-energy particle physics. These fundamental interactions are at the heart of physics and the physical sciences. En route to this long-term goal of a collider, this line of research could enable a new generation of laboratory-scale free-electron lasers and other photon sources.

• Creating capabilities to bring the power of Berkeley Lab science to the world. To take a few examples: A compact neutron source and detector system could enable sensing of the amount and distribution of carbon in the soil, a key to moving toward a low-carbon economy to protect the global climate. Compact charged particle sources are being used to research new methods of radiotherapy for cancer treatment. Compact accelerators creating precision photon sources allow X-ray images to be taken with much greater resolution and reduced radiation dose, improving medical screening and security applications. High field magnets would make a potential fusion energy source more compact and affordable. And high-intensity beams create new states of matter, including unique ways to form qubits for quantum information science.

• Building a new generation of lasers that combine high average power and high peak power in short pulses. Nearly-continuous lasers have already transformed many industrial processes, such as welding, by delivering kilowatts of average power with precision. Short-pulse lasers, lasting less than a trillionth of a second but with peak powers of hundreds of trillions of watts, unlock new physics interactions, including the keys to new laser-driven accelerators, tailoring material surfaces to create hydrophobicity or other properties, and more. We are pioneering the coherent combination of many ultrafast fiber lasers to create the short pulses at high repetition rates and average powers that are required for these and other applications.

These endeavors are made possible by our people. ATAP emphasizes mentorship to develop the national scientific workforce and educate the next generation – from students and postdoctoral researchers to career staff. ATAP’s strong divisional operations team is key to our success with complex projects, multi-agency engagement, and collaboration across the Laboratory. We place great emphasis on the Lab’s IDEA goals, including an active IDEA committee and participation in employee resource groups (I am an active member of the Lambda Employee Resource Group). We want ATAP to be a place where everyone feels that they are valued and that they can reach their full potential—a place where we don’t just accept differences, but celebrate them, which improves both the work environment and the results.

Who do you partner with at the Lab to be successful?

Because accelerators are essential tools across the sciences and for society, we partner broadly across the Laboratory. To give just a few examples, we are conducting experiments with the BioSciences Area on how the short pulses of ions produced by new plasma accelerators could improve cancer therapy. Together with the Nuclear Science Division, we are developing and testing sources of mono-energetic X-rays that could revolutionize sensitivity and reduce the radiation dose required for imaging needs across medicine, security, and industry. We partner with the Physics Division on combinations of accelerators and detectors that will advance our understanding of the structure of the universe through high energy particle physics. We create computer simulation codes and methods to understand and control complex systems in coordination with Computing Sciences and NERSC. We support Advanced Light Source operations and the Advanced Light Source Upgrade project with beam physics, diagnostics, and controls that push the facility beyond the state of the art; the result benefits soft-x-ray users throughout the physical and life sciences.

Developing new accelerators and new experiments means new configurations and capabilities, so we collaborate with the Environment, Health and Safety Division to bring those on line safely, even including testing of radiation detectors in new regimes of very short pulses. ATAP’s activities are based on a vital partnership with the Engineering Division, which provides advanced design work, dedicated mechanical and electrical shops working hand in hand with experiments, and specialized expertise and collaboration supporting our ability to execute major projects. The Laboratory’s and ATAP’s excellent support staff — including administrative services, finance management, facilities, human resources, communications and lab operations functions — are also essential to our ability to do these things. As Newton put it, we stand on the shoulders of giants. We are grateful to the many people who help us make the climb.