One of the most important and challenging projects in DOE’s Office of Science is LCLS-II, the Linac Coherent Light Source at SLAC. As part of a partnership with SLAC, Fermilab, Jefferson Lab, and Argonne National Laboratory, the Berkeley Lab team has continued making impressive progress through or toward production of our various contributions.

Meanwhile, our recently established Berkeley Accelerator Controls and Instrumentation Center has a feather in its cap already: Qiang Du of the Engineering Division and ATAP has been selected by the Office of High Energy Physics to its Early Career Research Program. This prestigious and competitive program will enable him to work on coherent combining of ultrafast laser pulses — a timely topic relevant to the next steps for the Berkeley Lab Laser Accelerator and beyond.

BELLA research has the potential for many spinoffs, and one of them is a candidate for the national security applications described in another hot-off-the-presses report from an LBNL-led team, Impact of Monoenergetic Photon Sources on Nonproliferation Applications.

All these achievements are made possible by people. With the workplace climate for women in high technology much in the news lately, I would like to reiterate that Berkeley Lab’s commitment to diversity and inclusion is also the policy of our division, and is something that I personally endorse. One of the most positive things I see in ATAP is an ever increasing number of women, including many at an early stage in their careers, working at the frontiers of science and technology or providing vital leadership and support services.

If you haven’t already, I recommend this essay by our own Laboratory Director, Mike Witherell. Resources for learning more are available through the LBNL Diversity and Inclusion website, including materials on implicit biases, as well as short videos and a game related to the recent series of talks by Dr. Steve Robbins.


Undulator modules, injector source, LLRF among highlights

SXR and HGVPU Undulator Deliveries Continue

Second pair of SXR modules arrive at SLAC August 9
Following the delivery of the first two production soft-X-ray (SXR) undulator modules in April, the second pair of SXR undulators arrived at SLAC in August (left). Berkeley Lab is responsible for development and delivery of these devices, currently under production at two vendors. Ultimately, a chain of 21 modules will make up the SXR FEL at SLAC. Based on experience with the first article, LBNL engineers have modified the production processes to further improve performance of the delivered devices.

Meanwhile, production of the HGVPU (horizontal gap vertically polarized undulator) for the hard-x-ray beamline is under way at external vendors, and the first magnetic modules have been shipped from the vendor in Finland to LBNL. Following magnetic measurements of these first articles at LBNL, they will be integrated into the mechanical assembly at another vendor before returning to LBNL for tuning.

Injector Source Fabrication and Particle-Free Assembly Continues

The VHF gun particle-free cleaning is complete and the anode mounted on the cathode in preparation for alignment and then welding of the final vacuum seal. Particle-free cleaning uses techniques involving dry-ice bombardment of the interior vacuum surfaces to remove particulates, and sensitive particle counters to validate cleanliness. Extreme cleanliness is vital to protecting the superconducting cryomodules downstream of it in the LCLS-II linac. The photocathode vacuum load-lock system has also been cleaned, and is packaged and crated for delivery to SLAC.

Shown here is one of the specially trained technicians performing final particle-free cleaning of the Injector Source gun cathode. A spray of dry ice, formed by expansion of high-purity CO2 gas expelled through a small nozzle, is directed onto the copper surfaces of the cavity. The blast of gas, and expansion of frozen droplets upon impacting the surface, dislodge particulates, leaving an extremely clean surface.

The work is performed at LBNL in a “class-100” cleanroom (no more than 100 particles of 0.1 µm dimensions, and proportionately fewer larger particles, per cubic meter).

Gun Amplifier Production Making Progress

The Injector Source gun is powered by 120 kW of VHF (186 MHz) power. LBNL engineers and scientists have specified the amplifier required to deliver this power, and the systems are being built by R&K Co. Ltd. In Fuji City, Japan. The sub-systems are now coming together, and factory acceptance tests are planned for September.

Production Success Isn’t Complete Without Quality Assurance

The LBNL LCLS-II team has been integrating Quality Assurance (QA) into activities from the early design stages, and production includes several stages of test and measurement of components to ensure they meet specifications. LBNL quality engineers and production engineers work closely with vendors to qualify their procedures, and make visits to oversee critical tests. On final delivery of equipment to SLAC and before installation in the LCLS-II facility, LBNL staff provide full documentation of as-built components and systems, an essential part of fulfilling our commitments for this DOE O413.3 Project.

LLRF System Earns Kudos in Final Design Review

The LCLS-II Low-level RF controls (LLRF) systems were reviewed by an external committee of experts in July. The system received very positive comments for the technical design, for which LBNL is responsible, and now has approval to become our next LCLS-II contribution to move into the design phase.


Berkeley Lab-led report highlights technique for detecting, identifying nuclear materials

Glenn A. Roberts, Jr., LBNL Public Affairs

Image - This image shows how a compact, precise photon beam (middle) could penetrate through 40 centimeters of steel (left side of image). The beam could be useful for detecting and identifying nuclear materials, among other uses. (Credit: Berkeley Lab)

This image shows how a compact, precise photon beam (red line) could penetrate through 40 centimeters of steel (left side of image). The beam could be useful for detecting and identifying nuclear materials, among other uses. (Credit: Berkeley Lab, University of Michigan)

A new, compact technique for producing beams of high-energy photons (particles of light) with precisely controlled energy and direction could “see” through thick steel and concrete to more easily detect and identify concealed or smuggled nuclear materials, according to a report led by researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).

[Editor’s Note: This technical document, Impact of Monoenergetic Photon Sources on Nonproliferation Applications, Idaho National Laboratory report INL/EXT-­‐17-­‐41137, is downloadable from the Office of Scientific and Technology Information.]

These photons are similar to X-rays but have even higher photon energy than conventional X-rays, which lets them penetrate thick materials.

Past techniques have had broad spreads in energy and angle that limited their effectiveness. New developments could bring the capabilities of highly precise, building-sized facilities to room-sized or mobile platforms that enable a range of high-priority nuclear nonproliferation and security uses.

This precision can simultaneously increase resolution while producing a lower radiation dose for many uses in and beyond nuclear security, such as:

  • Detecting contraband or explosives.
  • Verifying the contents of casks that store spent nuclear reactor fuel.
  • Monitoring nuclear treaty compliance.
  • Detecting a concealed nuclear device.
  • Characterizing hazards after a nuclear accident.
  • Industrial quality control – and potentially medical X-rays.

“This report is focused on what type of source is needed to have the biggest impact rather than what has been developed to date,” said John Valentine, Berkeley Lab’s program manager for National & Homeland Security. “It lays out the roadmap to realizing applications.” The report was prepared for the National Nuclear Security Administration (NNSA), a DOE agency responsible for national security-focused applications of nuclear science.

“One major application for this type of technology is the detection of concealed nuclear material – for example, hidden in cargo containers or a vehicle – but it has broad use for detecting other types of contraband,” said Cameron Geddes, a staff scientist in the Lab’s Berkeley Laboratory Laser Accelerator (BELLA) Center. Geddes led the preparation of the report with Bernhard Ludewigt, a staff scientist in the Lab’s Fusion Science and Ion Beam Technology Group, part of the Accelerator Technology and Applied Physics (ATAP) Division.

A “monoenergetic” photon source could be used to verify the contents of nuclear reactor fuel storage casks (top). The beam could be patterned in a “parallel” scan (bottom left) or a “fan” scan (bottom right). (Credit: Berkeley Lab, University of Michigan)

Geddes and Ludewigt worked with a team of scientists from Pacific Northwest, Idaho, and Lawrence Livermore national labs, as well as the University of Michigan, to conduct detailed simulations that showed the improved capabilities that the new techniques would make possible.

“Existing technologies commonly use so-called ‘Bremsstrahlung’ sources to detect and identify nuclear materials,” said Ludewigt. This kind of radiation source is not tightly directed and delivers a fan-shaped spread over a broad energy range of radiation. Those characteristics can limit imaging capabilities and require higher doses of radiation.

Known as a “monoenergetic photon source,” the new technology would have a tightly collimated beam – meaning its photons would travel nearly parallel to one another in a narrow path. Those photons would also have a narrow and precisely tunable energy range. These properties would reduce the radiation output needed during scans compared to other technologies in use today. They would also reduce the effect of undesired signals, such as noise from scattered photons, that can interfere with the detection of nuclear materials.

When scanning for hidden nuclear materials, Ludewigt said, “You don’t want to have to open up every container that has something dense in it.” The ability to quickly scan large objects, such as cargo containers, is also key, as millions of cargo containers pour into the U.S. every year.

The scanning technique’s beam must also be safe for humans who may inadvertently come into contact with it, Geddes added. “That means we need to perform detection with high specificity while keeping dose low, so that if someone is hiding in the cargo container the scan won’t hurt them,” he said.

Simulations show, for example, that scanning at two separate ranges of energy would enable operators to identify the general type of materials that are present. If an object is discovered in this initial scan that is so thick or dense that it requires a more deeply penetrating scan to explore its contents, then by tuning the energy to specific values the same photon source could be used to identify whether an item is nuclear material.

With very tight control over the beam energy, the new source could also identify the exact element – including isotopes of elements, which have a different atomic weight and can be important in gauging nuclear security threats.

Image - This diagram shows how a high-energy photon beam penetrates through a storage container to detect highly enriched uranium. (Credit: Berkeley Lab)

This diagram shows how a high-energy photon beam penetrates inside an unknown object (cube) to detect highly enriched uranium. (Credit: Berkeley Lab, Idaho National Laboratory)

The report also notes that the beam’s reduced radiation dose and increased specificity in materials detection could have a strong impact in other fields that use high-energy photons, including medical and industrial uses. Such a source would, for example, improve nondestructive industrial analysis – the ability to look inside machinery without the need for disassembly.

While building-sized particle accelerators have long been able to make precise, monoenergetic photon beams, new technology could shrink these systems, making them more affordable and compact to enable broad use.

“Instead of bringing the applications to the machine, we hope to bring the machine to the applications, whether that means scanning cargo, verifying treaty compliance, or many other uses,” said Wim Leemans, director of the Berkeley Lab Laser Accelerator (BELLA) Center and the Lab’s ATAP Division.

Berkeley Lab is among the leaders in the worldwide effort to develop new, compact acceleration technologies at its BELLA Center. BELLA uses lasers to generate a superhot state of matter known as a plasma, and to generate bunches of electrons and rapidly accelerate them to high energies over a very short distance.

Experiments have already shown that BELLA’s plasma-based accelerators can produce the types of electron beams needed to realize a controlled high-energy photon beam that would meet the requirements described in the report.

Geddes is leading a separate BELLA Center project to demonstrate a compact monoenergetic source. The beams would be generated by scattering of a separate laser beam off of the high-energy electron beam from a plasma accelerator to produce pulsed photon beams with a narrow range of energies and controlled angles, a process called Thomson scattering. The new report details how such beams could improve the identification and imaging quality of nuclear materials.

“We are testing new technologies that can reduce the massive scales and costs of next-generation accelerators, enabling us to explore new realms of physics,” Leemans said. These include next-generation high-energy particle colliders, and free-electron lasers that produce the world’s brightest X-rays. All of these demand faster pulsing rates for the lasers that drive the new sources, and R&D is also underway toward pulse rates that would enable the techniques outlined in the report.

This work is supported by the Office of Defense Nuclear Nonproliferation Research and Development in the Department of Energy’s National Nuclear Security Administration.


Excerpted from an article by Julie Chao of LBNL Public Affairs. Click here for the full story of all five ECRP recipients at LBNL this year.

Five scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) have been selected by the U.S. Department of Energy’s (DOE’s) Office of Science to receive significant funding for research through its Early Career Research Program.

Among them is Qiang Du, an electronics research scientist in the Engineering Division. His award is for “Scalable control of multidimensional coherent pulse addition for high average power ultrafast lasers,” selected by the Office of High Energy Physics.

Working with ATAP, Dr. Du will design, build, and demonstrate a scalable distributed digital stabilization control system for robust multidimensional coherent combining of ultrafast fiber lasers, and make it available as a general toolbox in ultrafast optics control. High average power ultrafast lasers are essential tools that support fundamental science and applications.

The program, now in its eighth year, is designed to bolster the nation’s scientific workforce by providing support to exceptional researchers during the crucial early career years, when many scientists do their most formative work. The five Berkeley Lab recipients are among a total of 59 recipients selected this year, including 21 from DOE’s national laboratories, chosen from a competitive review of about 700 proposals.

The scientists, who must be employees within 10 years past their PhD, are each expected to receive grants of up to $2.5 million over five years to cover year-round salary plus research expenses.

To Learn More…

For more information on all the winners and the award, go to DOE’s ECRP page.

ATAP is home to four earlier ECRP selectees: Chad Mitchell and Jeroen van Tilborg (2016), Danielle Filippetto (2014), and Tengming Shen (2012).


Tengming Shen, a researcher in ATAP’s Superconducting Magnet Program, the Berkeley Center for Magnet Technology, and the U.S. Magnet Development Program, has won the 2017 ICMC Cryogenic Materials Award for Excellence.

The award is given annually at the International Cryogenic Materials Conference to an individual, who is under 40 years of age by the application deadline, to recognize excellence in advancing the knowledge of cryogenic materials over recent years. Dr. Shen was cited for “outstanding research on superconductors especially Bi-2212: Processing, characterization, and advances towards practical applications.”

Shen, who came to ATAP from Fermilab in 2015, is working primarily on materials-science aspects of high-temperature superconductors such as Bi-2212 and Rare Earth Barium Copper Oxide (REBCO), which we and others are investigating for potential uses in next-generation accelerator magnets for high-energy physics as well as other applications.


Review Results in HL-LHC AUP CD-1/3a Recommendation

A recent Department of Energy review of the High-Luminosity LHC (HL-LHC) Accelerator Upgrade Project (AUP) found that it is thoroughly ready for the next phase — work toward the Critical Decision 2 milestone of a project baseline and a robust preliminary design — and that long-lead-time procurement of conductor should proceed. The Fermilab-led AUP is the framework for US efforts in the overall HL-LHC project, which will greatly increase the luminosity of the CERN collider. More than 12 years of work by ATAP, partnered with the Engineering Division, have resulted in two major roles in fabrication of interaction-region quadrupole magnets. The challenging task will take advantage of the strengths of three national laboratories. The Berkeley Center for Magnet Technology, a joint venture of ATAP and the Engineering Division, will fabricate Nb3Sn conductor into cables, which both Fermilab and Brookhaven National Laboratory will wind into coils. We will then assemble those coils into magnets, which Brookhaven will test. These quadrupoles will be the first major use of high-field niobium-tin superconductor, which is a key area of LBNL expertise, in an accelerator. Future issues of this newsletter will give details on progress.

Linac Innovation Makes It to Final Round of R&D 100

An ATAP and Cornell University team has developed a potentially disruptive approach to compact accelerators, called MEMS-ACCEL for its basis in micro-electromechanical systems (MEMS) technology. MEMS-ACCEL that has been named as a finalist for this year’s R&D 100 competition. From among the 170 finalists, the hundred most significant inventions of the year are scheduled to be announced in November. ATAP has won or been part of the winning team on 18 of these “Oscars of innovation” since 1985. Click here for the list of finalists, and revisit our June newsletter to to learn more about MEMS-ACCEL.


If you have an opportunity to represent what we do at LBNL and get children (and sometimes adults) excited about science, try one of our demonstration kits.

Over the years (especially for events like Open House, Daughters and Sons to Work Day, etc.), ATAP and the Lab’s Workforce Development and Education Office (WD&EO) have accumulated a variety of items to help people see science and technology in motion. Dr. Ina Reichel (left), ATAP Outreach and Diversity Coordinator, is the key resource for learning more about what’s available, how to use the kit safely and effectively, and the science curriculum points they convey.

The kits address various grade levels, and the demonstrations can range from five minutes or so to a class period or two.

If you have any nice hands-on or demonstration experiments that you are willing to share with other ATAP staff, please contact Ina Reichel and Joe Chew so that we can add them to the list.

Diffraction Was Popular Attraction at OUSD Science Fair

In May, Reichel and BELLA Center’s Cameron Geddes took one of the perennial favorites — WD&EO’s diffraction gratings kit — to Chabot Space & Science Center for the Oakland Unified School District’s annual Science Fair. The winners from each school give poster presentations (something they’ll do often if they pursue careers in science), enjoy the museum’s exhibits, and visit booths from the District’s Science Partners, including Berkeley Lab. We have brought hands-on science activities to the Fair, together with flyers for our science education programs, for a number of years.

The kit demonstrates diffraction gratings and the analysis of light. With a small diffraction grating that they can keep, visitors to our booth look at three light sources (incandescent, fluorescent and LED) and learn what it reveals about the way the light is emitted.

It’s a lesson not only about lighting and spectra and electromagnetic waves — important topics in their own right — but also about how scientists work, observing phenomena and then using their knowledge to explain the observations. Geddes says, “Once they understand the differences between the bulbs we bring, we then challenge them to identify bulbs around the room based on those characteristics, giving them a chance to explore and understand how scientific instruments help us see what the naked eye cannot.”

The demo attracted a great many of the several hundred students and parents stopped by our booth — no small feat considering that the nearby competition included an East Bay park ranger with a live snake! They went away with new physics-based understanding of why compact fluorescent and LED lamps are more efficient and new insight into what instrumentation can reveal about hidden worlds all around us.

To Learn More…

Contact Ina Reichel for more information about how to get involved with students and other members of the community and how to select from among the available demos. A Web page surveying the various demo kits is being developed.


Be In the Know in Emergencies with LabAlert
August 2 was a memorable day. In the morning there was lockdown due to an intruder who was thwarted in an attempt to steal a vehicle. Later in the day, the site was evacuated when a wildlands fire in the Oakland hills made the power company warn us about a possible precautionary shutdown of our main electrical feed.

It was a reminder that timely and accurate information is a precious thing in an emergency. LabAlert brings the latest news on what’s happening and what to do straight to your cellphone. Click here to learn more and sign up. The free service is activated only in emergency situations and the information is direct and to the point. We encourage employees, students, and onsite affiliates to sign up.