Many exciting prospects lie before us in the coming years in ATAP. To take best advantage of them, we have made some organizational changes in coordination with the Laboratory Directorate and our partners and funding agencies.
Accelerator physicist Dr. David Robin of ATAP has been named project director of the Advanced Light Source Upgrade (ALS-U). Fernando Sannibale, presently the principal investigator of the Advanced Photoinjector Experiment at LBNL, will take Robin’s place as leader of the ALS Accelerator Physics program in ATAP and will also serve as the ALS Division Deputy for Accelerator Operations and Development.
In recognition of the importance of computer simulation in today’s accelerators, we have established a new program, Accelerator Modeling, that focuses on developing advanced computational techniques for understanding particle accelerators and beams. Dr. Jean-Luc Vay will head the new program.
Dr. Soren Prestemon is the new Director of the Berkeley Center for Magnet Technology. Prestemon replaces Dr. Stephen Gourlay, who is now serving as Director of the U.S. Magnet Development Program, a recently created DOE high-energy-physics program.
David Robin Named ALS-U Project Director; Fernando Sannibale Becomes ALS Division Deputy for Accelerator Operations and Development
Accelerator physicist Dr. David Robin of ATAP has been named project director of the Advanced Light Source Upgrade (ALS-U). He was chosen for this role by LBNL Director Michael Witherell in collaboration with ATAP Director Dr. Wim Leemans and ALS Director Dr. Roger Falcone.
Fernando Sannibale, presently the principal investigator of the Advanced Photoinjector Experiment at LBNL, will take Robin’s place as leader of the ALS Accelerator Physics program in ATAP and will also serve as the ALS Division Deputy for Accelerator Operations and Development.
Robin, a senior scientist in the ATAP Division and a Fellow of the American Physical Society, has been with LBNL since receiving his doctorate from the University of California, Los Angeles in 1991. After spending two years working on the design of the PEP-II B-Factory, he joined the ALS accelerator physics staff, leading the Accelerator Physics Group starting in 1999, then became ALS Deputy for Accelerator Operations and Development in 2005.
As group leader, Robin led highly successful ALS accelerator upgrades, including the superbend upgrade (completed in 2001) and the top-off upgrade (completed in 2009). He recently accepted the 2015 Secretary of Energy Achievement Award for the 2013 brightness upgrade of the ALS on behalf of the team led by his deputy, Christoph Steier.
“Dave has devoted much of his career to keeping the ALS at the forefront of light-source performance,” said Leemans. “Technologies, user demand, and opportunity are coming together to let us build the ultimate version of the ALS, and Dave and his team are in a great position to lead us there.”
ALS-U will enable the production of highly focused beams of soft x-ray light that are up to 1000 times brighter than that of the existing ALS by employing an improved electron storage ring. The new ring will use a dense array of powerful, compact magnets known as a multibend achromat (MBA) lattice, which has been successfully demonstrated at the new MAX-IV facility in Sweden. In combination with other improvements to the accelerator complex, the new machine will produce highly coherent x-ray beams capable of probing matter with unprecedented detail.
“Now the real work begins,” added Robin, noting that CD-0 is just the start of the project, kicking off the conceptual design and project definition phase that must undergo rigorous reviews before achieving the next major DOE milestone, CD-1.
The ALS got its start in ATAP’s predecessor organization, the Accelerator and Fusion Research Division. ATAP continues to provide accelerator physics and technology leadership for the many upgrades of the machine.
Continuing to improve the ALS in the meanwhile
To take Robin’s place as head of the ALS Accelerator Physics Program, Leemans and Falcone named Fernando Sannibale as the ALS Division Deputy for Accelerator Operations and Development.
Sannibale, a senior scientist in ATAP and a Fellow of the American Physical Society, has more than 25 years of experience in accelerator physics. His expertise includes storage rings for colliders and light sources, high-brightness electron sources, free-electron lasers (FELs), and accelerator instrumentation.
In addition to being a member of the ALS Accelerator Physics Program, for the last seven years Sannibale has been the principal investigator for APEX, the Advanced Photoinjector EXperiment. APEX is an injector test facility developed to test a novel concept called the “VHF-gun,” an electron source conceived at LBNL and optimized for operation in high-repetition-rate x-ray FELs. Based on the successful results at APEX, the VHF-Gun has been selected as the electron source for the Linac Coherent Light Source-II, the high-repetition rate free-electron laser being built at SLAC National Accelerator Laboratory.
“David and Fernando are internationally admired accelerator physicists, they have made enormous contributions over many years at the ALS, and I am very pleased to see them engaged in these critical roles for our facility and our users,” said Falcone. “It’s a pleasure to work with them and the entire ALS accelerator physics team.”
“With the ALS-U CD-0 approval, the years to come will be an exciting but challenging period,” said Sannibale. “The needs of the operational ALS with its 2,500 users and the growing resource demand from the new ALS-U, must be carefully managed and coordinated by the two divisions’ leadership teams to ensure effective progress and success for both activities. I am looking forward to playing my part.”
New ATAP Program Focuses On Accelerator Modeling
In recognition of the importance of computer simulation in today’s accelerators, ATAP Division Director Wim Leemans has established a new program, Accelerator Modeling, that focuses on developing and applying advanced computational techniques to the understanding of machines and beams.
ATAP senior physicist Jean-Luc Vay will head the program, which draws its core personnel from the Berkeley Lab Laser Accelerator Center (BELLA) and the Center for Beam Physics, among our most computationally intensive efforts.
“These are tremendously exciting times to work in accelerator modeling,” Vay said. “There is great demand for high-performance codes and for transitioning them to future supercomputing architectures. A dedicated modeling program will be an opportunity to use LBNL’s strengths to serve these needs of the accelerator community.”
After earning his doctorate in 1996 from the University of Paris, Vay came to LBNL as a postdoctoral researcher and was appointed as a career staff member in 2000. He received the 2013 US Particle Accelerator School Prize for Achievement in Accelerator Physics and Technology for original contributions to the development of novel methods for simulating particle beams, particularly the Lorentz boosted frame techniques, and for the successful application of these methods to multi-scale, multi-species problems. Vay also received the 2014 NERSC Award for Innovative Use of High Performance Computers for his work on boosted frame and novel spectral decomposition techniques.
“Modeling is crucial to how we design accelerators today, and even how we operate them,” says Leemans. “Concentrating our efforts with this new program will help us lead the way to higher performance modeling, which means better accelerators.”
That requires high-performance, high-fidelity modeling of complex processes that develop over a wide range of space and time scales. This in turn calls for next-generation “exascale” computing power, with performance 50 to 100 times greater than that of today’s typical supercomputers, as well as software customized to take full advantage of it.
Vay recently received funding from DOE’s Exascale Computing Project for an effort in modeling of advanced particle accelerators. It will push toward the ambitious ten-year goal of modeling a chain of 100 laser-plasma acceleration stages in less than a week — hopefully less than a day — of computer time.
“Accelerator modeling is an opportunity to help lead the way to exascale applications,” says Leemans, noting that transforming science through exascale computing is one of Director Witherell’s strategic priorities for the Laboratory.
The recent report by the Accelerator R&D Subpanel of HEPAP, the High Energy Physics Advisory Panel, concurs. The Subpanel observed that “advancing the capabilities of accelerator simulation codes to capitalize on the drive toward exascale computing would have large benefits in improving accelerator design and performance.” Coupled to algorithmic advances, it will “enable reaching the ultimate goal of realtime virtual prototyping of entire accelerators” — the detailed and accurate end-to-end modeling that has long been a dream of the accelerator simulation community.
“An opportunity to help lead the way to exascale applications”
— ATAP Director Wim Leemans
ATAP has long been among the leaders in accelerator modeling, often working together with LBNL’s Computing Research Division and National Energy Research Supercomputing Center (NERSC), as well as colleagues at other laboratories and universities in the U.S. and abroad. A recent article by NERSC's Kathy Kincade discusses an example, the code WARP IV, and puts it in the context of the computing and visualization synergies to be found at LBNL.
Those existing efforts are already coming together through Berkeley Lab Accelerator Simulation Toolkit (BLAST), which spans various ATAP programs, and the nascent multi-institutional Consortium for Advanced Modeling of Particle Accelerators (CAMPA). The new Modeling Program will bring together these activities, already under Vay’s coordination, into a unified framework.
A Project to Take Accelerator Simulations to the Exascale
The Department of Energy’s Exascale Computing Project (ECP) has announced support for 15 critical research applications for next-generation supercomputers, and ATAP will lead one of them: “Exascale Modeling of Advanced Particle Accelerators,” with Vay as principal investigator.
This project supports the practical and economic design of smaller, less-expensive plasma-based accelerators. Turning plasma accelerators from a promising technology into a mainstream scientific tool depends critically on high-performance, high-fidelity modeling of complex processes that develop over a wide range of space and time scales. Lawrence Livermore National Laboratory and the SLAC National Accelerator Laboratory will also participate in the project.
With 50 to 100 times the performance of today’s typical supercomputers, “exascale computing will be able to accomplish in minutes to hours what presently would take days to weeks,” adds Vay. This will enable accelerator designers to perform far more-detailed and higher-fidelity simulations and to examine more-complex phenomena.
The ten-year challenge taken up by the proposal is the modeling of a chain of up to a hundred plasma acceleration stages in less than a week, and ideally less than a day.
The recent report by the Accelerator R&D Subpanel of HEPAP, the High Energy Physics Advisory Panel, observed that “advancing the capabilities of accelerator simulation codes to capitalize on the drive toward exascale computing would have large benefits in improving accelerator design and performance.” Coupled to algorithmic advances, such as the Lorentz boosted frame approach, adaptive mesh refinement, scalable spectral electromagnetic solvers, and numerical Cherenkov instability mitigation methods, it will “enable reaching the ultimate goal of realtime virtual prototyping of entire accelerators” — the detailed and accurate “end to end” modeling that has long been a dream of accelerator simulation.
“This accelerator modeling project embodies the new paradigm of combining experimental and computational methods to advance a critical technology,” said James Symons, LBNL’s Associate Laboratory Director for Physical Sciences. “Realizing the potential of plasma-driven accelerators will impact fields ranging from health care to manufacturing to basic research.”
|Supercomputer simulations of plasma-based accelerators typically use a “moving window” to restrict the simulation area to a region of interest that encompasses the laser beam and the portion of wakefield that accelerates the electron beam. In this small-scale simulation meant to illustrate the physics, a laser beam (red and blue disks) propagating through an under-dense plasma displaces electrons, creating a wake that supports very high electric fields (pale blue and yellow), that can accelerate an electron beam (white) to high energy in a short distance. While the simulation box is spatially much smaller, the number of time steps that are required to simulate the crossing of the laser through the plasma is still very large, typically over a million. Exascale computers, 50-100x more powerful than today’s typical supercomputers, will be game changers for what we can feasibly model.|
ECP Work Will Be Next Stage of an Ongoing Effort
“We’ve spent years preparing to take advantage of this opportunity,” Leemans observes.
Vay coordinates the Berkeley Lab Accelerator Simulation Toolkit (BLAST) effort and the emergent multi-laboratory Consortium for Advanced Modeling of Particle Accelerators (CAMPA). Vay also leads the NERSC Exascale Science Applications Program (NESAP) project on Advanced Modeling of Particle Accelerators. NESAP was launched in 2014 to prepare for NERSC’s newest supercomputer.
Exascale To Be a Big Part of Lab’s Future, and Vice Versa
Of the 15 fully funded ECP proposals, Berkeley Lab will lead two and participate in four others. An additional seven proposals received seed funding; Berkeley Lab will lead three and participate in two others.
“These awards reflect our extensive experience and expertise in computational science across a wide range of disciplines, including accelerator design, subsurface flows, cosmology, combustion, chemistry,” said Kathy Yelick, Associate Laboratory Director for Computing Sciences. “Our applied mathematics and computer science expertise will be needed to develop applications tailored to exascale systems.”
To learn more…
Kathy Kincade of NERSC has written a feature article, “The Incredible Shrinking Particle Accelerator,” that sets some of the modeling work in the larger context of high-performance computing at LBNL and the synergies and support to be found here.
Prestemon Named BCMT Director; Gourlay to Focus on New U.S. Magnet Development Program
ATAP Division Director Wim Leemans has named Dr. Soren Prestemon as director of the Berkeley Center for Magnet Technology. Prestemon replaces Dr. Stephen Gourlay, who is now serving as Director of the U.S. Magnet Development Program, a recently created DOE high-energy-physics program.
“Launching the new national magnet development program and taking BCMT into its second year opens up great opportunities for two of our top people,” says Leemans.
Prestemon came to LBNL as a research engineer in 2001 after earning his doctorate from Florida State University — host of the National High Magnetic Field Laboratory, which is one of the partners in the new U.S. Magnet Development Program. Previously he had studied mathematics at Université Joseph Fourier and engineering at the Institut Polytechnique de Grenoble.
“Soren brings a unique perspective to BCMT,” he adds. “He’s a member of LBNL’s Engineering Division, has worked closely with the Advanced Light Source on magnet development, and for two years was head of our own Superconducting Magnet Program. Since the creation of ATAP he has been my Division Deputy for Technology. The whole idea of BCMT is to bring together magnetics expertise from ATAP and Engineering, so he’s a great fit.”
“In providing innovative and groundbreaking technology, combined with a disciplined engineering approach, Soren has been a key resource in developing magnets and undulators for LBNL’s facilities and the broader national and international programs LBNL is engaged in, ” adds Henrik von der Lippe, Director of the Engineering Division.
Prestemon takes over BCMT at an exciting time in accelerator-related magnetics. Besides colliders for high-energy physics, new-generation synchrotron-light sources — both free-electron lasers such as Linac Coherent Light Source-II, being built at SLAC, and diffraction-limited light sources based on storage rings, like LBNL’s proposed ALS Upgrade — are being envisioned and pursued. Such facilities will require pushing forward the state of the art in the design, construction, and measurement of magnets of all kinds. Other applications currently under development include electron cyclotron resonance ion sources, medical-treatment gantries and fusion-energy facilities. Many of these projects involve multi-institutional and even international partnership.
“The BCMT will help foster communication channels and coordination,” says Prestemon. “This approach is truly the best way to integrate design and construction into applications with our partners.”
Advanced magnets: essential parts of the future of HEP
One of the most magnet-dependent sciences is collider-based high-energy physics, which probes the fundamental nature of matter and energy with machines like CERN’s Large Hadron Collider. Nature does not give up such deep secrets easily or cheaply, and magnets play an important role in the technology and cost of colliders.
Gourlay heads the U.S. Magnet Development Program, an LBNL-led multilaboratory initiative recently launched by the DOE’s Office of High Energy Physics. The MDP has an ambitious technical mission to push multiple aspects of the performance of superconducting magnets while reducing their cost. Its success is considered key to future high-energy physics proton colliders.
In ATAP’s Superconducting Magnet Program, Gourlay was instrumental in three successive field-strength records for accelerator-style magnets. “Our program has an unbroken series of field-strength records, and what’s more, they’ve done that with a series of different technologies, always innovating,” observes Leemans.
LARP, the Large Hadron Collider Accelerator Research Program, also flourished here under Gourlay’s leadership. One of LARP’s results, achieved in partnership with Brookhaven National Laboratory and Fermilab, is a focusing quadrupole design for a beam-luminosity-increasing upgrade of the LHC. These magnets will make the LHC the first collider to use niobium-tin superconductor in a major role. Magnet designs that realize the promise of this high-performing but hard-to-work-with material have been a hallmark of Gourlay’s LBNL career and will be a prominent theme of the Magnet Development Program.
The other charter members of the partnership — Fermilab and Florida State University’s National High Magnetic Field Laboratory — have strong capabilities and distinguished achievements of their own, making for a powerful and well-rounded combination. “With the combined resources and infrastructure of the MDP partners, we have an extraordinary opportunity to take the U.S. leadership in high field superconducting magnets to an unprecedented level,” Gourlay says.
Gourlay started his career at Fermilab in 1985 after earning his Ph.D. from the University of California, Davis. Working at first on the user-science side of high-energy physics, he turned his attention to magnets in 1988, contributing to the Tevatron Collider and the Superconducting Super Collider. After a one-year appointment at CERN, he came to LBNL in 1997, serving twice as Superconducting Magnet Program head and for eight years as director of ATAP’s predecessor, the Accelerator and Fusion Research Division.