I earned my degrees at Goethe University in Frankfurt, Germany, doing my graduate research at Lawrence Livermore National Laboratory on ion-solids interactions. In a postdoctoral fellowship there, I researched ultrafast (~10 fs) electronic excitation of solids, nanostructuring (“nano” was new then), and materials analysis. In 2000, I came to Berkeley Lab to work on the “front-end system” that the Accelerator and Fusion Research Division (now known as ATAP) was developing for the Spallation Neutron Source being built at Oak Ridge. Here is a link to my CV for those interested in the details.

During those days I also began work on the hardware foundations of quantum computing, exploring spin qubit ideas — work that continues, and is now aligned with a burgeoning Labwide emphasis on quantum information systems. (To learn more about this, see the related article, and visit the Berkeley Quantum website.) My other research interests include materials far from equilibrium (as studied, for example, with intense ion beam pulses and plasmas) and novel accelerator concepts (such as MEMS-based multi-beam accelerators).

Later years brought opportunities to lead the Ion Beam Technology Group, then to serve as head of the Fusion Science and Ion Beam Technology Program. Throughout my time at the Lab I have been fortunate to be able to work with many colleagues in ATAP and our partners in the Engineering Division as well as with colleagues across the Lab.

The generation and ensuing acceleration of ion beams is one of the central legacies of the Division’s (and Berkeley Lab’s) origins. Driving advanced accelerator concepts (most notably based on laser-plasma acceleration in the BELLA Center) and the development and application of ion sources, compact accelerators and low-energy accelerator “front ends” has continued to be an area of excellence for us.

I have always been attracted to the idea of the scientist as a maverick who likes to learn and try new things. And I have learned that innovation and creativity can be balanced with long term vision and the discipline to complete things.

Teaching a graduate course on Accelerators and Beam Physics in UC-Berkeley’s Nuclear Engineering Department last Spring, together with Carl Schroeder, proved to be a lot more fun then I had expected (all these slides to prepare…) and I see a really wonderful opportunity here to foster and grow our longstanding connection with new joint projects and students from campus who work with us.

As is required for cutting-edge work in accelerators, we are very good at many different things, and what’s more, we talk to each other. Cross-pollination among our specialty areas is something that benefits both our own endeavors and our many collaborations (across the lab, with campus, nationally and internationally). As interim director, I look forward to finding new ways to foster this success pattern.

“In the search for an interim director, we were looking for someone who exemplified Berkeley Lab’s approach to team science and appreciated the whole of the accelerator field. Thomas brings a rigorous technical knowledge that is broad as well as deep, and a history of collaborative work with enthusiasm for disruptive ideas.”
—ALD for Physical Sciences James Symons

In ATAP, we are laying the scientific foundations of future particle accelerators. These accelerators can make the difference in advancing our understanding of the most fundamental aspects of matter and energy in the universe and they enable exciting new applications.

In ATAP, theory, modeling and simulations iterate swiftly with experiments to drive advanced accelerator concepts. We are leading the world in mastery of laser-driven plasmas that accelerate electrons to record energies at the BELLA Center. We are developing near-term, high-impact applications of laser-plasma accelerators in areas ranging from radiography to medicine. Coherent combining of fiber laser pulses might be the ticket to reaching high average power with short pulse lasers. Ultrafast electron diffraction at MHz repetition rates (HiRES) now enables collaborative users to track the multi-scale structural evolution of materials. ATAP plays key accelerator physics and technology roles in the ALS-U project, the upgrade of Berkeley Lab’s Advanced Light Source that will serve thousands of users for years to come. We are pushing the envelope in magnet development to reach higher fields with new materials and are leading the US Magnet Development Program. We use lasers, plasmas and beams to drive materials and matter far from and study novel properties under these extreme conditions — now with users and collaborators as part of LaserNetUS (see article below). We apply beams of neutrons to image carbon in soil. We develop multi-beam ion accelerators based on MEMS that might enable massive scaling of beam power in a table top setup. We use and develop machine-learning techniques to advance accelerator science, and we have connected to the new wave of Quantum Information Science with precision control techniques and new ideas on spins and photons for quantum sensing and communication.

Throughout our diverse endeavors in accelerator technology and applied physics, a key to our success is the ability to integrate our capabilities in theory, modeling and simulation, and fabrication and operation of facilities. Supporting all this, we are fortunate to have strong and dedicated technical-support and business-operations teams so we can work efficiently and safely.

I very much look forward to this opportunity. I am excited about working with you, supporting ongoing programs, and helping to develop the seeds of new ideas into new and thriving R&D directions.

Eric Esarey has been performing research on intense laser-plasma interactions, advanced accelerator concepts and novel radiation sources for over 30 years. After receiving his PhD in 1986 in plasma physics at MIT, he worked for 12 years at the Naval Research Laboratory. During that time, he and his colleagues pioneered fundamental theory on nonlinear laser-plasma interactions that described the physics of laser-plasma accelerators (LPAs) and carried out groundbreaking experiments on LPAs.

Esarey joined Berkeley Lab in 1998 as a physicist within the theory group of the Center for Beam Physics, where he continued researching LPAs and related phenomena. He helped found the BELLA Center and grow it into the world leading program that it is today. Esarey had previously served as BELLA Center’s Deputy and as Senior Scientific Advisor to the ATAP Division Director. He now succeeds BELLA’s founding director, Wim Leemans, who has left LBNL for a position at DESY.

Schenkel describes Esarey as “a visionary and longtime leader in the field of LPAs with an integrating perspective on the program.”

Esarey’s recent honors include the AAC Prize from the 2018 Advanced Accelerator Concepts Workshop (an event that he will chair in 2020). Among his numerous publications are comprehensive review articles on plasma accelerators that are highly cited within the community. A technical backgrounder accompanying the announcement 2018 Nobel Prize in Physics explained the LPA concept with a diagram originally published in Physics Today by Leemans and Esarey. (See the related article, “2018 Physics Nobel Cites an ATAP Application.”)

Esarey’s deputies are described by Schenkel as “capable, energetic, and with diverse scientific backgrounds,” exemplars of a strong BELLA team “hungry for achievement.”

Carl Schroeder has been a leader of the theoretical and modeling efforts that support BELLA’s experimental work and future applications. After earning his doctorate at UC-Berkeley in 1999, followed by a postdoctoral fellowship at UCLA, he joined LBNL in 2001. His research interests range across BELLA’s intellectual portfolio, including intense laser-plasma interactions, plasma-based accelerators, advanced acceleration concepts, novel radiation sources, and free-electron lasers. “Carl is a theoretical leader not only in BELLA’s current work, but also in the long-term push toward an LPA-based lepton collider,” says Schenkel.

“Ultimately,” he adds, “mastery of laser drive plasma accelerators will enable us to explore physics beyond the Standard Model, and to make strides in understanding the nature of matter and energy, and do so with a much smaller physical and financial footprint than today’s collider technologies. Carl is driving this vision and is laying the foundation for its practical implementation.”

Cameron Geddes is the lead experimentalist in the new BELLA Center leadership team.

“Cameron has a very strong foundation in high-energy and ultrafast lasers, and since his days as a graduate student has been a driving force and leader in the projects he works on,” says Schenkel.

Geddes has led a variety of the Center’s experimental projects. This includes a new laser facility for one of the many promising near-term applications of laser-plasma accelerators: compact quasi-monoenergetic gamma-ray sources for nuclear nonproliferation and security inspection. He has broad research experience in plasma physics, which at Berkeley Lab has included experimental designs for the PW laser, demonstration of novel concepts in particle injection and beam quality, staging experiments, high energy density science, and large-scale simulations. After working at Lawrence Livermore National Laboratory and Polymath Research on inertial-fusion-related laser-plasma interactions, he earned his doctorate at UC-Berkeley and LBNL in 2005, receiving the Hertz and APS Rosenbluth dissertation prizes. He joined the LBNL staff upon graduation. “Cameron brought a strong foundation in high-energy and ultrafast lasers to us, and since his days as a graduate student has always been a leader in everything he works on,” says Schenkel.

The path forward

BELLA Center is a world leader in the study of intense laser-plasma interactions and advancing the development of LPAs. Research there has demonstrated increasing single-stage electron beam energy gains, now at several GeV, together with lower-energy experiments on staging and on achieving high beam quality.

Going to ever higher energies will require using one LPA stage’s output as the input to the next, achieving more energy than is practical for a single stage. BELLA has achieved a first demonstration of staging. A major next step is to develop and implement a multi-GeV staging experiment. This very exciting and important effort has now been started with funding from DOE High Energy Physics.

In addition to electron beam acceleration, BELLA is exploring the applications of laser-plasma accelerated electron beams, e.g., with programs to develop compact radiation sources based on LPA electron beams.

Higher average laser power will be required for a lepton collider and also for many near-term LPA applications, and the BELLA Center is performing R&D to advance the development of these lasers. Fiber-based laser systems are among the candidates for this key enabling technology.

“Eric, Cameron, and Carl are all distinguished individuals and team leaders in their disciplines, and have been working together for many years to keep BELLA at the forefront of laser-plasma acceleration,” Schenkel says, adding, “BELLA is sure to enjoy continued growth and achievement under their leadership.”

Berkeley Lab Joins LaserNetUS

To help foster the broad applicability of high-intensity lasers, Berkeley Lab is a partner in a new research network called LaserNetUS. The network will provide U.S. scientists increased access to the unique high-intensity laser facilities at BELLA Center and at eight other institutions nationwide operating high-intensity, ultra­fast lasers.
Expanding access to key capabilities
“High-intensity and ultrafast lasers have come to be essential tools in many of the sciences, and in engineering applications as well,” said James Symons, Berkeley Lab’s associate laboratory director for its Physical Sciences Area.

Such lasers have a broad range of uses in basic research, manufacturing, and medicine. For example, they can be used to recreate some of the most extreme conditions in the universe, such as those found in supernova explosions and near black holes. They can generate high-energy particles for high-energy physics research (being explored at the BELLA Center) or intense X-ray pulses to probe matter as it evolves on ultrafast timescales. Laser-based systems can also cut materials precisely, generate intense neutron bursts to evaluate aging aircraft components, and potentially deliver tightly focused radiation therapy to tumors, among other uses.

The petawatt-class lasers of the LaserNetUS partners generate light with at least 1 million billion watts of power. A petawatt is nearly 100 times the output of all the world’s power plants, and yet these lasers achieve this threshold in the briefest of bursts. Using a technology called “chirped pulse amplification,” which was pioneered by two of the winners of this year’s Nobel Prize in physics, these lasers fire off bursts of light shorter than a tenth of a trillionth of a second.

Maintaining U.S. leadership in a fast-moving global endeavor
The U.S. was the dominant innovator and user of high-intensity laser technology in the 1990s, but now Europe and Asia have taken the lead, according to a recent report from the National Academies of Sciences, Engineering, and Medicine titled “Opportunities in Intense Ultrafast Lasers: Reaching for the Brightest Light.” Currently, 80 to 90 percent of the world’s high-intensity ultrafast laser systems are overseas, and all of the highest-power research lasers that are currently in construction or have already been built are also overseas. The report’s authors recommended establishing a national network of laser facilities to emulate successful efforts in Europe.

LaserNetUS is holding a nationwide call for proposals that will allow any researcher in the U.S. to request time on one of the high-intensity lasers at the LaserNetUS host institutions.. The proposals, due March 18, will be peer reviewed by an independent proposal review panel. This call will allow any researcher in the U.S. to apply for time on one of the high intensity lasers at the LaserNetUS host institutions. The initial “Run 1” experiments are expected to take place in the second half of calendar 2019.

2018 Physics Nobel Cites an ATAP Application

The 2018 Nobel Prize in Physics cited LPAs and BELLA’s acceleration achievements as examples of the benefits of the research being honored, and illustrated the concept with a diagram from a paper by Wim Leemans and Eric Esarey.

The prize was shared by three pioneers in the science, technology, and applications of lasers. Two of the laureates — Gérard Mourou and his then doctoral student, now a professor, Donna Strickland — won for a breakthrough that (among its many other benefits) made BELLA Center possible.

Their Nobel-winning research brought “chirped pulse amplification,” a method of generating high-intensity, ultra-short pulses, to lasers. In a mere three pages, their 1985 paper “Compression of Amplified Chirped Optical Pulses” (Optics Communications 56, 3 (1 December 1985), pp. 219-221) sparked a revolution. The concept was implemented widely and almost immediately, ending a decade-long plateau in laser performance.

Today, CPA and follow-on developments are used near-universally at the peak-power frontier of very large research lasers, and also to increase the peak power of relatively small lasers for a wide variety of industrial and medical applications as well as research. (To take just one of many examples, some of you may be reading this with vision corrected by LASIK surgery, a technology made feasible for widespread use by CPA.)

We were immensely gratified to see laser-plasma acceleration, and specifically the multi-GeV electron beams obtained at the BELLA facility, mentioned as one of the examples of the benefits of CPA in the Nobel committee’s scientific background document. The BELLA Petawatt system is a 1 Hz repetition rate Ti:sapphire laser based on the CPA technique pioneered by Strickland and Mourou. In addition to the discussion, the Nobel backgrounder used a conceptual diagram of the LPA principle from the 2010 White Paper of the ICFA/ICUIL Joint Task Force on High Power Laser Technology for Accelerators —a figure that had originally appeared in an article by Wim Leemans and Eric Esarey in the March 2009 issue of Physics Today.

The white paper was produced by a joint task force, chaired by then-ATAP Division Director Wim Leemans, of the International Committee on Future Accelerators and International Committee on Ultra-high Intensity Lasers, and was based on a workshop series held first at GSI and then here at LBNL. The notional BELLA follow-on, which we call k-BELLA for its kilohertz repetition rate / kilowatt average power performance class, is an example of such a next-generation laser.

CPA is also one of the techniques used in an exciting collaborative project being conducted through our Berkeley Accelerator Controls and Instrumentation (BACI) Center: development of a laser system that uses “coherent combining” to achieve both high peak power and high average power from arrays of fiber-optic lasers.

The scientific stature and the widespread, ongoing societal impact of the research by Drs. Mourou and Strickland, as well as their co-laureate Dr. Arthur Ashkin, are formidable. (Ashkin is a pioneer of laser trapping and the inventor of “optical tweezers” that use lasers to grasp tiny physical particles such as bacteria or viruses. His work had already figured into the 1997 Nobel Prize in Physics for our former Lab director and Secretary of Energy Steven Chu, who had worked with Ashkin at Bell Labs.) Their achievements have given us both game-changing tools and inspiration. This is a time for all of us to be proud of the important role we play as research pioneers and the resulting benefit to humankind.

Three ATAP Endeavors Featured in APS-DPB Annual Highlights

Each year the APS-DPB newsletter asks leaders in the field to look back on the year’s the most important and timely topics in accelerators and beams. The 2018 edition focuses on US projects and programs, including three ATAP efforts: Lasers for Plasma Accelerators; Modeling Future Accelerators on the Eve of Exascale Computing; and The U.S. Magnet Development Program.

In “Lasers for Plasma Accelerators” (pp. 13-15), Almantas Galvanauskas of the University of Michigan, then-ATAP Division and BELLA Center Director Wim Leemans, and Jay Dawson of Lawrence Livermore National Laboratory summarize the challenges and opportunities for building ultrafast lasers with both high average and high peak power, as needed by future generations of laser-plasma accelerators.

“Modeling Future Accelerators on the Eve of Exascale Computing” (pp. 16-17), by Jean-Luc Vay, head of ATAP’s Accelerator Modeling Program, describes the prospects for powerful, high-fidelity tools for the design, optimization, and perhaps even predictive control of particle accelerators. A rendering from a plasma accelerator simulation, using the Berkeley Lab Accelerator Simulation Toolkit code WARP3D, was chosen as the cover illustration for the report.

In “The U.S. Magnet Development Program” (pp. 24-27), Soren Prestemon, Director of the USMDP (and ATAP’s Deputy Division Director for Technology), together with Fermilab’s Gueorgui Velev, the USMDP Deputy Director, survey the goals and progress of this Berkeley Lab-based, multi-institutional effort to develop transformational magnet technologies for high-energy physics.

The issue was edited by Alysson Gold and Nihan Sipahi, Early Career Members-at-Large of the APS-DPB Executive Committee.

These are just a few of the 15 articles about exciting technical topics in our field. Click here for the Newsletter.

Synergies of Quantum Computing, Fusion Energy Outlined in New Report

Fusion and plasma sciences and the emerging field of quantum computing and communications could have a variety of mutual benefits, according to the recent report of the Fusion Energy Sciences Roundtable on Quantum Information Sciences (QIS).

The Roundtable, chaired by Thomas Schenkel and Bill Dorland of the University of Maryland, outlines three priority research opportunities in each of two broad categories: “Quantum for Fusion” and “Fusion for Quantum.” A wide variety of other sciences could also benefit.

“Quantum for Fusion” covers what this new processing and communication paradigm might do for certain classes of computation-hungry problems in plasma sciences and fusion energy, as well as instrumentation and control. “Fusion for Quantum” discusses the use of fusion- and plasma-related techniques in making and simulating quantum information systems.

“QIS is an excellent opportunity to do things that were not previously feasible,” said Schenkel, who in addition to being ATAP Interim Director heads our Fusion Sciences and Ion Beam Technology Program, and who has collaborated internationally to help develop an enabling technology for one approach to quantum computing. “Fusion and plasma researchers have an opportunity to both help build and benefit from this new computing paradigm.”

Berkeley Lab has a variety of efforts covering many aspects of QIS, most coordinated by Berkeley Quantum, an initiative that involves both the Lab and the adjacent UC, Berkeley campus. Schenkel is part of a Berkeley Lab team, led by the Physics Division’s Maurice Garcia-Sciveres, that is developing quantum sensors for a dark matter search. Gang Huang of ATAP and Engineering is contributing to QIS efforts as well, developing field-programmable gate array readouts for the quantum testbed effort of Irfan Siddiqi.

To learn more…
Click here to download the report from the DOE Office of Fusion Energy Sciences.

Future of Storage-Ring-Based Light Sources Explored at Diffraction-Limited Storage Ring Workshop

The opportunities and challenges of building the fourth generation of storage-ring-based light sources, such as Berkeley Lab’s Advanced Light Source Upgrade (ALS-U), were the subject of the 6th International Diffraction Limited Storage Ring Workshop (DLSR 2018). The workshop, held October 29-31, 2018, at Berkeley Lab, was jointly organized by the ALS Division (Elke Arenholz and Ken Goldberg) and ATAP Division (Simon Leemann).

Synchrotron light facilities—electron storage rings that produce intense, laserlike x-ray beams—have become vital infrastructure for a broad range of sciences. As the science and technology of these rings has progressed, accelerator researchers are finding ways to build rings that approach the “diffraction limit,” with an electron beam so orderly that, for a given photon wavelength, both its emittance and that of the photon beam produced from it are almost zero.

DLSRs have become a hot topic in the synchrotron-radiation community; some 150 registered participants came from 25 labs around the world to discuss progress toward achieving truly diffraction-limited x-rays from high-brightness storage ring sources. The workshop emphasized both technical challenges and new research opportunities, and focused on the design, construction, commissioning, and operation of accelerator, beamline, and experimental systems that will be required.

The ultra-low electron beam emittance that will be available at these new and upgraded facilities will enable dramatic improvements in many areas of x-ray science, especially for experiments that directly require transversely coherent x-ray wavefronts. Worldwide, ten upgrades of existing machines and ten more new facilities are in some phase of study, R&D, or construction.

Berkeley Lab is on the front lines of this revolution. ALS-U, now in a design phase, exemplifies this push toward the fundamental, theoretical limits of what can be done. It will transform the ALS, which was among the bellwethers of the third generation of synchrotron light sources, into a fourth-generation source, ready for another 20 years of providing the beams needed for cutting-edge research.

		Scenes from the future of synchrotron light: At left, with Halloween close at hand, Elke Arenholz, deputy for operations at the ALS, worked a seasonal theme into the summary talk on Experimental Systems. Upper right: Chair Andreas Streun (Swiss Light Source, left) and speaker Riccardo Bartolini (Diamond Light Source, right) fielded a question. Lower right: At the poster session Christoph Quitmann (MAX IV, left) and Will Waldron (LBNL, right) discussed fast kickers, one of the technical challenges for ALS-U.

The workshop presented an opportunity to showcase efforts underway for ALS-U. Dave Robin gave an overview of the ALS-U Project in the Monday plenary session, while several speakers from the ALS and ATAP Divisions covered various aspects of ALS-U in their breakout presentations. They included Stefano De Santis of ATAP’s Berkeley Accelerator Controls and Instrumentation program (BACI), who presented an overview of fast kicker requirements for DLSRs and described progress made on fast stripline kicker development for injection in ALS-U.

This was just part of a diverse program. It had been seeded with topic suggestions from an international scientific program committee, which elicited many interesting contributions. The workshop presentations were well attended and prompted lively follow-up discussion during breakouts. Additional discussion sessions built into the schedule allowed for an exchange of thoughts on progress thus far as well as remaining challenges and possible solutions.

Much positive feedback was received for the workshop, which benefited greatly from solid support by Berkeley Lab’s Yeen Mankin, Jason Templer, Candy Lao, and Michele Pixa.

After a well-attended close-out came the announcement that the next DLSR Workshop would be held in the summer of 2020 in Lund, Sweden. It will be hosted by MAX IV, the first source to come online using the multibend achromat (MBA) lattice—the arrangement of magnets generally chosen for the fourth-generation rings being studied or planned, including ALS-U.

Tour guides from ATAP who have specific knowledge of the ALS are especially needed. (Particle accelerators, with their ongoing rich heritage of contributions to our knowledge of the atom, nucleus, and subatomic particles, are regarded as nuclear facilities for merit-badge purposes, and the Advanced Light Source is the focus of many of their experiences.)

However, you don’t need to be a scientist or engineering and technology professional to contribute to Nuclear Science Day for Scouts. Logistics and chaperoning are key parts of a good experience, so come help the Scouts learn that people from all walks of life play many positions in team science.

To learn more…
• Visit the Nuclear Science Day for Scouts website. The site also has a link for Scout leaders to sign up their troop. (Note: If you’re involved in Scouting, signing up as a volunteer increases the likelihood that your troop will be among those accepted for this space-limited and significantly oversubscribed event.)
• You can also learn more through this Berkeley lab photostory and sign up for the event’s Twitter feed.
• Contact Ina Reichel, ATAP’s Education and Outreach Coordinator, for more information about volunteering.
• The signup form for volunteers can be found here.