Raised in a farmhouse without electricity, Lambertson would become known for seminal contributions to some of the most advanced and nuanced aspects of particle accelerators, making possible the infrastructure of discovery.
Besides the “Lambertson septum” magnet that is a key part of so many accelerators, Glen made essential contributions to the understanding and control of instabilities in charged-particle beams. The most notable of the many applications in this area are the highly successful transverse and longitudinal feedback systems used at the ALS and PEP-II. Other outstanding contributions include stochastic cooling techniques, damping of higher-order modes in radio frequency cavities, and the understanding of the electron-cloud effect in modern storage rings. He also taught a microwave technology class at several US Particle Accelerator Schools, and in his characteristically quiet and unassuming way, influenced and mentored many accelerator scientists and engineers over the years.
Glen was born January 14, 1926, near the small coal-mining town of Paonia, Colorado, in a farmhouse that had no electricity and only one water faucet. From a young age he was raised by a single mother, along with his sister and older brothers, during the height of the Great Depression, doing his homework by the light of a kerosene lantern.
A good student, Glen graduated from high school at 16 and earned a scholarship to the University of Colorado, Boulder—the first in his family to go to college. Just after his sophomore year, the chemical engineering major had to put his education on hold when he was drafted into the Army.
“Oh God, I’m in charge”
Glen’s daughter Tali Pinkham and his son Roy recalled their father’s account of his wartime experiences. Having grown up in Colorado, he served in the “ski troops” (a capability not actually used during the war) of the Tenth Mountain Division, and fought in their campaign to push German forces out of the Apennines in northern Italy in 1945.
In the battle to take Mount Belvedere, his squad leader was wounded and the assistant squad leader was simultaneously killed by a hand grenade. Glen realized that it was up to him to lead the attack on his squad’s objective, a German gun emplacement, whereupon he thought, at age 19, on his first night of combat, “Oh God, I’m in charge.”
Glen went forward to shoot at the gun emplacement. He had two close calls with German “potato masher” hand grenades that night, and got wounded by friendly fire. A medic gave him morphine and he lay on the battlefield the rest of the night. In the morning he awoke to see German prisoners of war being marched downhill; the Tenth Mountain Division had taken Mount Belvedere.
In an army hospital, Glen’s life was saved by a wonder drug that was just then coming into mainstream use: penicillin. The battle had cost him a kidney and a rib, and he underwent multiple surgeries. He received the Purple Heart and was presented with the Bronze Star by General George P. Hays himself, the commander of the division.
Glen would not go into combat again, but was kept in Italy to do administrative work in a POW camp. After the war, he oversaw the task of sending prisoners back to their hometowns by train. He recalled that the POWs from eastern Germany would try to avoid getting sent back to that region, where they would be under the control of Soviet soldiers.
After a bout with appendicitis, Glen finally came home in 1946, and was able to resume his undergraduate studies at the University of Colorado.
Westward to the subatomic realm
At 22, Glen went to UC-Berkeley, where he earned a Master of Arts degree in physics. He began work toward his doctorate, but never completed it, as he was recruited by Berkeley Lab in 1949 and found accelerator technology to be a compelling interest.
Those years also brought a blind date with Betty Jean Smith, a graduate student at Berkeley. They married in 1950 and would remain together until she passed away in 2017.
Glen’s career began as an operator at the 184-inch Synchrocyclotron, occasionally with the Lab’s founder and director Ernest O. Lawrence reaching over his shoulder “to turn up a knob.” (Lawrence, a hard driver, wanted to push things to the point where they started to spark.) Moving to the new Bevatron, then the world’s highest-energy accelerator, he might have been part of the Nobel Prize-winning discovery of the antiproton in 1955, but a competing team went first. The following year he was a member of the team that used the Bevatron to discover the antineutron.
That would have been a promising start to any particle physics career, but the technology that provided the beams was in an exciting era of rapid progress as well. It was the beginning of the “Big Science” era, a concept born at Lawrence’s lab, in which interdisciplinary teams worked together on projects whose scale was uniquely suited to a national laboratory.
Glen’s career became more and more focused on accelerator technology. In the late 1960s, he helped invent a means of resonant extraction that could better divert beams out of the circular Bevatron and through evacuated tubes into an external particle beam hall. The “Lambertson septum” is used for beam injection and extraction in essentially all of today’s most powerful and important accelerators, such as the Large Hadron Collider at CERN. His inventions over the next four decades trace the history of advanced accelerators.
When Fermi National Accelerator Laboratory was formed in the 1960s, he was recruited by Robert Wilson, but soon returned to Berkeley. His association with Fermilab would remain long and productive, though, contributing to proton-antiproton (p-pbar) collider development, particularly in beam cooling (techniques to make a particle beam more orderly for sufficient interaction rate at experiments). In the late 1970s, following shortly after the developments by Simon Van der Meer of CERN in stochastic cooling, he and his team from Berkeley were the first to demonstrate the feasibility of stochastic phase-space cooling of antiprotons in a pilot experiment at the 200-MeV Fermilab cooling test ring. This technique would be an essential part of Tevatron p-pbar operation. He worked with Alvin Tollestrup of Fermilab in developing an electronic feedback system for stochastic cooling, based on a detector called the Schottky pickup. This work helped enable the Tevatron users’ independent validation of CERN’s discovery of the W and Z Bosons and ultimately Fermilab’s discovery of the top quark. His techniques were adopted for rings at Brookhaven National Laboratory as well.
In the mid 1970s he led the Experimental Superconducting Accelerator Ring (ESCAR) project, a first attempt to build a small (4 GeV) superconducting accelerator. The goal of ESCAR was to obtain data and experience for planning the larger superconducting machines of the future. While funds were not available to complete the project, two quadrants of dipoles were built and successfully tested, along with the necessary cryogenic and control system infrastructure. Part of the ESCAR legacy at Berkeley Lab is one of the world’s leading programs in superconducting magnets.
Glen also contributed to the design of the Superconducting Super Collider, numerous Snowmass studies for particle physics, analysis of feedback control of space-charge instabilities at Berkeley Lab’s Advanced Light Source, and radiofrequency devices and system design for control of beam instabilities at PEP-II.
Berkeley Lab’s Jose Alonso, whose scientific and management career had a long overlap with Glen’s, described him as “one of those people we all looked up to, the guru for instrumentation and beam dynamics.”
Mentoring and inspiring a new generation of scientists and engineers
The mentorship that Glen had enjoyed in his early days at the Lab, he gave in turn. Generations of accelerator scientists and engineers have benefitted from his gentle and unassuming guidance. Longtime Berkeley Lab colleague Swapan Chattopadhyay, now at Fermilab and Northern Illinois University, was one of his protégés as a graduate student at Berkeley in the mid 1970s. He recalls Glen as a great teacher and mentor who could not only apply physical intuition to difficult subjects, but explain them very lucidly, and who taught at the US Particle Accelerator School on many occasions.
SLAC’s John Seeman worked with Glen in the conceptual design phase of the PEP-II B-meson “factory,” an extremely challenging electron-positron collider built at SLAC in the early-mid 1990s and operated through 2008. He recalls how Glen helped with very detailed calculations and designs for the electromagnetic characteristics of some the most high-powered and beam-interactive components of the storage rings. These devices included megawatt copper RF cavities with higher-order-mode loads and also kilovolt stripline beam feedback kickers; the difficulty was making sure that the ampere beam currents did not destroy these in-vacuum components. Seeman recalls how “Glen’s ability to visualize the electromagnetic effects and their consequences made him crucial for our project. He had a tremendous grasp of the resulting beam heating and pulsed effects on the components and, thus, knew what to do about them.”
He adds, “In addition to being an excellent accelerator physicist, he was a very personable fellow and a great friend to the whole project team.”
John Corlett, now Berkeley Lab’s project management officer, recalls his days as a young scientist, when Glen was a personal and professional role model to him. He cites Glen was very influential in understanding beam stability in storage rings, and in designing broadband feedback systems that control the charged particle bunches in these rings. Early days at the ALS demonstrated high-frequency feedback systems, for which Glen’s contributions in design were critical. Following these demonstrations, Glen was a leading participant in the team that designed and built feedback systems for PEP-II, which were essential to maintain the high current beams stored in the B-Factory rings.
Though he left formal employment in 1991, Glen was one of the many Berkeley Lab scientists to continue their contributions in retirement, working on an impedance study of the LHC Y-Chamber, as well as the muon accelerator program. He remained a contributor to particle accelerator science and technology via conferences and workshops into the 21st century.
Berkeley Lab scientist Harvey Gould, who worked with a long-retired Lambertson on a team developing focusing and decelerating elements and a storage ring for neutral polar molecules, recalls, “At 80 years old, he was just about the fastest learner I have worked with and had the best grasp of effects and consequences. We presented a poster at an accelerator conference and were visited by most of the big names in the field, including a Nobel Laureate or two. They had come by in hopes of finding and talking to Glen. Glen was, of course, at one of the sessions seeing what new things he could learn about.”
Hiroshi Nishimura, who worked with him at the Advanced Light Source and then on atomic and molecular beams, adds, “Glen was generous with his time, kind in his explanations, and skilled at bridging the generational gap. All who were privileged to work with him will miss him.”
Recognition of his contributions included election to Fellowship in the the American Physical Society (1989), the US Particle Accelerator School Prize for Achievement in Accelerator Physics and Technology (1991), and the American Physical Society’s 2006 Robert R. Wilson Prize for Achievement in the Physics of Particle Accelerators. Berkeley Lab’s Lambertson Beam Electrodynamics Laboratory was named in his honor.
A life in full
To colleagues, so many of whom he would call friends as well, he was a figure of towering capability, yet a delight to work with. To his family, he was gentle and kindly Grandpa Glen, a man of good nature and bad puns.
Tali recalls life at their Art Deco home in the Oakland hills as a parade of visiting scientists from around the world. Along the way came a sabbatical at CERN in Geneva, along with a trip to Russia that Tali remembers as a major influence on him. The influence of his stay at CERN included his taste in cars; he drove a series of Citroens, and enjoyed working on them over the weekends. His experiences in Europe influenced their taste in food and drink (he was a lover of fine wine) as well; and he and Jean traveled the world in retirement.
An avid skier until age 82, he taught the sport to all seven of his grandchildren. In 1969 he designed an A-frame cabin and had it built near Donner Pass, “every surface finished to perfection,” as Tali recalls, much as if it were one of his RF devices at work.
Glen was preceded in death by his wife Jean and his siblings Wayne Lambertson, George Lambertson, and Mary Draper. He is survived by children Tali Pinkham and her husband Daniel Pinkham, Roy Lambertson and his wife Leah Lambertson, and Dean Lambertson and his wife Mary Gaines, along with grandchildren Hannah Pinkham, Claire Pinkham, Andrew Pinkham, Clayton Lambertson, Elena Lambertson, Kelly Lambertson, and Trevor Lambertson.
The input and assistance of family members Tali Pinkham and Roy Lambertson, and colleagues Jose Alonso, John Byrd, Swapan Chattopadhyay, John Corlett, Ben Feinberg, Harvey Gould, Derun Li, John Seeman, and John Staples, was invaluable in preparing this appreciation of Glen’s life and work. Photos courtesy Tali Pinkham and Roy Lambertson except as noted.