He and his team are working to transform high-T _c superconducting materials into practical magnet conductors in order to build a spectrum of powerful superconducting magnets impossible with low-T _c superconductors such as niobium-titanium (Nb-Ti) and niobium-three-tin (Nb ₃Sn). One goal is to use these new materials to build a high-field accelerator dipole that is 2.5 times more powerful than the 8.3 T Nb-Ti LHC main dipole, by taking advantage of their excellent ability to carry high current amid high magnetic fields (up to 100 T at 4.2 kelvins).

The work, if successful, will likely also open new avenues to building magnets similar in power to Nb-Ti and Nb ₃Sn magnets but operating at 20-77 K.  These would be potentially cheaper to operate than Nb-Ti and Nb ₃Sn magnets, which typically work at the liquid-helium temperatures of 1.8 or 4.2 K.

Bismuth-2212 is among the high-temperature superconductors being investigated by the program. Shen and his team are working to transform high-T _c superconducting material into practical magnet conductors in order to build a spectrum of powerful superconducting magnets impossible with traditional superconductors such as niobium-titanium (NbTi) and niobium-three-tin (Nb ₃Sn).

One goal is to use these new materials to build a high-field accelerator dipole that is 2.5 times more powerful than the 8.3 T Nb-Ti LHC main dipole, by taking advantage of their excellent ability to carry high current amid high magnetic fields (up to 100 T at 4.2 kelvins). The work, if successful, will likely also open new avenues to building magnets similar in power to NbTi and Nb ₃Sn magnets but operating at 20-50 K, potentially much cheaper to operate than NbTi and Nb ₃Sn magnets, which typically work at the liquid-helium temperatures of 1.8 or 4.2 K.

To effectively generate magnetic fields, practical superconductors need to carry a high engineering current density, J _e, of 600 A/mm ² over long lengths. (J _e=I _c/A: the critical current of the superconductor divided by the cross section of the composite superconducting wire.)  Tengming and his collaborators have succeeded in understanding microstructures and mechanisms that control I _c in superconducting wires of Bi-2212 (the only multifilamentary high-temperature superconducting cuprate round wire). Leveraging an industry, university, and national lab collaboration under the framework of ATAP-headquartered US Magnet Development Program, the team recently improved the J _e of Bi-2212 industrial wires to 1000 A/mm ² at 4.2 K and 27 T and demonstrated that high J _e and excellent quench properties are possible with coils fabricated from high-current Bi-2212 Rutherford cables. They are building prototype accelerator magnets using a canted-cosine-theta design developed by Shlomo Caspi and colleagues in ATAP’s Superconducting Magnet Program.

His several other current endeavors include collaborations with Fermilab and Composite Technology Development, Inc., in Colorado a to develop advanced resin and insulation technologies for Nb ₃Sn accelerator magnets; with Berkeley Lab’s National Center for Electron Microscopy and the University of California, Berkeley to develop 1-kelvin Nb-Ti superconducting electron microscopes; with Brookhaven National Lab,  KEK and Kyoto University to develop HTS magnets for a high radiation environment; and with an ATAP team led by Lucas Brouwer to develop achromatic, cryogen-free high-T _c magnets for proton therapy gantries.

Tengming is a former Peoples Fellow at Fermilab and recipient of a prestigious Early Career Research Program award from the U.S. Department of Energy, Office of High Energy Physics. He received his Ph.D. in electrical engineering from the Florida State University in 2010 with a thesis based on work at the National High Magnetic Field Laboratory.

The Roger W. Boom Award is named in honor of the late emeritus professor from the University of Wisconsin. Dr. Boom’s career spanned more than thirty years, during which he motivated a great number of young scientists and engineers to pursue careers in cryogenic engineering and applied superconductivity. This award was created by the CSA to be given to a young professional (under 40 years of age) who “shows promise for making significant contributions to the fields of cryogenic engineering and applied superconductivity. The spirit of the Boom Award is to recognize young people for their pursuit of excellence, demonstration of high standards and clear communications.

I have always considered Berkeley Lab a unique laboratory. Throughout my career, I have worked on the R&D of superconducting magnets for particle accelerators. This activity is usually carried out in laboratories dedicated to particle accelerators for nuclear physics or high energy physics applications. Instead, the work performed by the Lab’s Superconducting Magnet Program (SMP), which I joined in February 2020, is done within the framework of a multiprogram science laboratory. The broad spectrum of scientific activities, which include, in the ATAP Division, different technologies of particle accelerators, and, in the other division, energy, environment, computing and bio science, make Berkeley Lab an incredibly stimulating environment. And this is what attracted me here.

From your standpoint, what were the highlights and challenges you had to overcome in FY2020?
Ahh, 2020! How will we ever forget this year?! Well, shelter-in-place was established due to the spread of the COVID-19 in the Bay Area just a few weeks after I started working in the Superconducting Magnet Program. So, adjusting to what has been recurrently called the “new normal” was not easy. Working amidst the uncertainty of the course of the pandemic was for me, and I imagine for many others, the biggest challenge. But I must say that I have been impressed by the resilience of the group and of the Lab in general, and by how everybody, really everybody, worked hard and managed to adjust their work style and schedule in such a way that we could continue to carry out advanced R&D in these difficult times.

What will you focus on in FY2021?
I hope that one of the focuses for next year will be to go back to “good old normal”, characterized by in-person meetings and face-to-face discussions with colleagues on the next generation of superconducting magnets. Apart from this social aspect, and more specifically on the SMP activities, we will continue assembling 4.2 m long Nb ₃Sn magnets to be shipped to CERN for the High-Luminosity project. For sure, new and interesting analysis on magnet performance will come from the large amounts of data generated by these magnets. Also, we are entering the engineering design phase of the Test Facility Dipole, a large aperture magnet for High energy and Fusion applications, which will explore the limits of Nb ₃Sn superconducting technology. Finally, as part of the Magnet Development Program, we will continue the R&D towards the next generation of particle accelerator magnets, addressing quench performance and the use of new “High-Temperature” superconductors. So, I am sure it will be a very exciting year for the superconducting magnet community. 

Teamwork at its best! The first PSPS was unprecedented, and we had to achieve vertical launch. All Lab Operations and Scientific divisions collaborated effectively to power down the equipment, ensure a safe and secure mode throughout the PSPS, and work with a truly dedicated Facilities group during re-energization. All the Mission Support Officers helped each other, and my existing network of relationships across the Laboratory proved extremely helpful. We were all committed to bringing everyone back to work safely.

What was the biggest challenge you faced last year with the PSPS?
We were still bringing equipment back up from the first PSPS when we had to begin planning for the second one. Coordinating site access for staff who needed to check on labs or equipment was a challenge at first. IT came up with a great solution, creating a live editable Google Sheet that allowed EOC staff to organize site access. By the second PSPS, we knew our roles and worked even more smoothly and effectively together.

What will you do differently this year if the Lab needs to go into shutdown and then return to full operations?
The biggest additional challenge this year would be observing COVID-19 hazard control measures while working together in the EOC and not being at the same table or room. Finding ways to make the most of virtual presence will be important. For longer-duration PSPSs, selected scientific/technical staff will need to conduct walkthroughs to check status of research labs/equipment. Prioritizing re-energization of key infrastructure such as chillers and HVAC will be required to expedite the restart of research equipment.

Glen was born January 14, 1926, near the small coal-mining town of Paonia, Colorado. From a young age he was raised by a single mother, along with his sister and older brothers, during the depth 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 (center) and 10th Mountain Division comrades, New York City, 1946

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. The 19-year old 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.

L-R: William Wenzel, Bruce Cork, Glen, and Oreste Piccioni, discoverers of the antineutron in 1956. (LBNL photo)

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 CERN’s discovery of the W and Z Bosons at CERN and ultimately Fermilab’s discovery of the top quark. His techniques were adopted for rings at Brookhaven National Laboratory as well.

Making connections

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 Robert R. Wilson prize of the American Physical Society (2006).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

Glen, Jean, and two of their seven grandchildren at Donner Pass

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 includes 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.

The Daresbury years. Left: When Alan started there in 1968, Daresbury was a high-energy physics laboratory, and he worked on a diamond target for NINA, a 5-GeV electron synchrotron. Intended for particle physics, NINA soon came to be used as a synchrotron radiation source. The SRS, first purpose-built synchrotron light source, was approved for construction in 1974 and produced first light in 1980. Right: Celebrating the last SRS magnet to be measured at their new computer-controlled magnet measurement facility, ca. 1979. (From “Accelerator Science at Daresbury—the early years,” a slide presentation by Vic Suller of Louisiana State University)

“He was one of the founding fathers of the ALS,” recalled Howard Padmore, ALS photon science development lead. Other colleagues had a ready list of his numerous accomplishments and contributions.

“Alan had a major impact on the ALS in the design, construction, commissioning, and early operations phases,” said David Robin, now director of the ALS Upgrade Project. “He encouraged the accelerator team to push the boundaries of the accelerator to see what was possible. Almost everything we tried was new and we learned so much,” he added.

Alan’s work was at the very root of the ALS in the mid-1980s—pioneering the third generation of synchrotron light sources—and he played a key role in the team effort that led to its smooth commissioning and operation. Fernando Sannibale, current ALS deputy for accelerator operations, explained, “Following up on an original idea by Gaetano Vignola, Alan refined and implemented the novel triple-bend-achromat lattice at the ALS.” This type of “lattice,” or array of magnets that steer the electron beam in its orbit, was later adopted for a number of high-brightness synchrotron light sources worldwide in the energy range of the ALS.

The intricacies of designing such a machine were compounded by the realities of repurposing a historical building atop a hill and near a fault line, but the team persevered, and the ALS achieved first light in 1993. Alan’s expertise in accelerator design continued to prove essential as the ALS moved to expand its portfolio. Together with Werner Joho of Paul Scherrer Institute, he had another idea that would greatly extend the user service at the ALS: installing superconducting bend magnets.

Each of the 12 sets of triple-bend achromats was made up of a series of three magnets, the magnets on either end mirroring each other. This symmetrical arrangement enabled the center magnet to be replaced without undesirable effects, so superconducting dipoles were substituted in the center position in three sectors of the storage ring. The three Superbends were commissioned in Fall 2001 and have provided light for Nobel-prize-winning work and world-leading programs in structural biology, high-pressure diffraction, microdiffraction, chemical crystallography, and tomography ever since.

Alan served as deputy director of the Accelerator and Fusion Research Division and as head of its Superconducting Magnet Program before his retirement from the Lab in 2008. His experience made him the natural candidate to lead the development of the Australian Synchrotron. Impressed with their visit to Berkeley Lab, a senior delegation from Australia asked Alan to be the technical director for their design task group.

“Alan was highly regarded in his field,” wrote Dean Morris, head of operations for the Australian Synchrotron. Alan’s four years there helped the project quickly design a storage ring and achieve first light in a relatively short period of time. “He made a lot of friends when he was in Australia and will be sorely missed by many,” said Morris.

Former Director of the Accelerator and Fusion Research Division Bill Barletta encapsulated Alan’s personable and effective management style, saying, “He had superb relations with the technical and administrative staff and was an ideal source of ‘ground truth’ when those who knew firsthand would generally clam up to ‘the management.’” Robin agreed, saying, “Alan was a dynamic and supportive leader. As a young accelerator physicist, I remember those first few years of operation being tremendously exciting, fun, and fruitful.”

The global accelerator community mourns not just the loss of Alan’s expertise, but also his friendship and joie de vivre. Besides his distinguished contributions to accelerator physics, Alan greatly enjoyed life away from work and was an avid sailor, sports car enthusiast, and center of a wide network of friendship. Padmore said, “He was a larger-than-life person who lived life to the fullest and was the life and soul of ALS in its early years.” Kem Robinson, retired senior physicist and former head of the Lab’s Engineering Division and Project Management Office, concluded, “Alan wasn’t afraid to take on whatever needed to be done for the greater good. Yes, he will be missed.”

After an article by ALS Communications, with contributions by Joe Chew, John Corlett, Steve Gourlay, Cindy Lee, Howard Padmore, Ina Reichel, David Robin, Fernando Sannibale, and Tony Warwick. Top photo courtesy Christine Jackson.