Berkeley Lab

Derun Li Retires from ATAP, Moves to DOE

Head shot of Derun Li

Derun Li

Derun Li, Senior Scientist and Head of our Berkeley Accelerator Controls and Instrumentation (BACI) program, retired from Berkeley Lab on October 31st, 2022.

Derun will soon begin a full-time encore career with DOE’s Office of High Energy Physics. There he will succeed L.K. Len as head of the General Accelerator R&D Program, a crucial program developing the new accelerator methods that enable the next generation of projects and future particle colliders. Derun has been a part-time detailee to OHEP for the past year.

In 2017, after three years as its deputy, Derun became head of the BACI Program—a successor to the Center for Beam Physics, where he started his Berkeley Lab career. He has led the program in developing new controls and instrumentation, which increasingly drive the capability of complex accelerator systems. This includes world-class programs in feedback and machine learning controls across a variety of application areas including accelerators; low-level RF; laser pulse combining; quantum information science; advanced RF structures including structures in strong magnetic fields; and novel beam sources and diagnostics.The Division is starting an international search for the next head of this exciting and vital program.

Derun arrived at Berkeley Lab in 1997 after earning his doctorate under the renowned S.Y. Lee at Indiana University in 1995, followed by a postdoctoral appointment under Professors S. Schultz and N. Kroll at the University of California-San Diego. Joining the Center for Beam Physics, he developed innovative radiofrequency systems for some of the most challenging efforts of their times, including the Advanced Light Source, the PEP-II B-meson “factory” at SLAC, and free-electron laser proposals, as well as design studies for components of the Large Hadron Collider at CERN and the Relativistic Heavy Ion Collider at Brookhaven.

He managed the Lab’s Muon Accelerator Program, leading the US teams for normal-conducting RF cavity R&D for muon ionization cooling channels. The UK-based Muon Ionization Cooling Experiment (MICE) was another key area of contribution to a future muon collider. Collaborating with Oxford University, he led the development of a novel RF cavity design with thin beryllium windows for MICE, along with superconducting solenoidal coupling coils. Derun also headed the LBNL team for spectra-solenoidal magnets. A landmark paper describing a successful ionization-cooling demonstration appeared in Nature in 2020.

Derun also led the development of high performance radiofrequency-quadrupole linacs (RFQs). This type of accelerator is especially well suited to being an injector for the highest-quality low-energy protons and ions in an accelerator complex, but poses a number of unique design and implementation challenges.
Derun’s success with RFQs began with a design study for a spare for the Spallation Neutron Source, which is now a major DOE neutron science user facility at Oak Ridge, and culminated in PIP-II, the Proton Improvement Plan at Fermilab. He led the LBNL team that designed, constructed and delivered Berkeley Lab’s first continuous wave (CW) RFQ to PIP-II. The PIP-II RFQ has been successfully commissioned (exceeding its design performance) and is presently the injector of the PIP-II accelerator complex—the future of high-energy physics in the US, helping enable Fermilab’s high-intensity neutrino physics program.

Continuing his technical as well as his leadership contributions, most recently he has headed the Berkeley Lab team for the development of APEX-II, which will be the next generation of the highly successful Advanced Photoelectron Experiment (APEX). Derun had earlier worked on rf-cavity studies for APEX and the APEX-based injector for the LCLS-II at SLAC. APEX has also led to a state of the art facility at BACI for photoinjector, beam and diagnostic development and for Ultrafast Electron Diffraction, known as HiRES. Since 2019, he has been the senior team leader and PI at Berkeley Lab overseeing the ongoing collaborations with SLAC on LCLS-II and LCLS-II HE.

Please join me in congratulating Derun on 27 years of technical and leadership contributions to some of our most challenging and important work, and wishing him the best in his new role of shaping and supporting research toward the next generation of accelerators.