Berkeley Lab

Recent ATAP News

FS&IBT Technology is a First “Pitch” Hit

Dr. Thomas Schenkel has won the inaugural LBNL Pitch Competition, held Nov. 3 by LBNL’s Innovation and Partnerships Office (IPO).

Schenkel, ATAP’s Division Deputy for Technology and head of the Fusion Science and Ion Beam Technology Program, won with his pitch for MEMS-ACCEL. A miniaturized ion acccelerator developed in collaboration with Cornell University, MEMS-ACCEL is also a finalist in this year’s R&D 100 competition.

Left to right: Thomas Schenkel, Arun Persaud, Peter Seidl, and Qing Ji On pitch: From left, ATAP researchers Thomas Schenkel (representing the team in the competition), Arun Persaud, Peter Seidl, and Qing Ji.

In the Pitch Competition, nine research teams with entrepreneurial prospects from across the Laboratory put forth their business case in front of a panel of experts — a process familiar on the road to the marketplace, and for which they have been trained through opportunities like IPO’s I-Corps program.

Schenkel will represent Berkeley Lab in a 9-entrant DOE-level I-Corps pitch competition on Nov. 29.

“Communication skills play a big part in bridging the gap between R&D and industry,” says ATAP Director Wim Leemans,” adding, “I’m looking forward to seeing Thomas represent us at the DOE level — and to the problems that the technology itself can solve. Efforts like this make the private sector more aware of it, and that’s a win for everyone.”

ATAP NEWS, OCTOBER 2017

DIRECTOR’S CORNER

Researchers in our Berkeley Laser Accelerator Center and Accelerator Modeling Program, working with international colleagues, have validated a way to both circumvent a source of errors and improve performance when using an important class of computer models to predict the performance of laser-plasma mirrors. The LBNL-led US Magnet Development Program set a new record — by a dramatic margin — for the current density in magnets made with high-temperature superconductor. We’ve continued contributing to the future of photon science with deliverables for LCLS-II and ongoing research in anticipation of the ALS Upgrade, while our ion-beam expertise continues to enable improvements in magnetic resonance spectroscopy.

PIC-ING A BETTER MAXWELL’S SOLVER FOR LASER-PLASMA MIRRORS

With the advent of petawatt class lasers, the very large laser intensities attainable on target should enable the production of intense high-order Doppler harmonics from relativistic laser-plasma mirror interactions. At present, modeling these harmonics with particle-in-cell (PIC) codes is extremely challenging, as it requires accurate description of tens to hundreds of harmonic orders on a broad range of angles.

In a new study published in the journal Physical Review E, BELLA Center graduate student Guillaume Blaclard, with colleagues from ATAP’s Accelerator Modeling Program and from CEA Saclay in France, describes effects that can potentially degrade the simulation results — and validates a new modeling method that could circumvent the problem and improve performance too.

A potential source of error

Standard finite-difference time-domain (FDTD) solvers for Maxwell’s equations — the solvers employed in most of the particle-in-cell (PIC) codes that are widely used in accelerator modeling — induce numerical dispersion when dealing with waves in a vacuum. This numerical artifact can in turn induce a spurious angular deviation into harmonic beams. (For another example of studies and mitigations of a different numerical artifact, see “Avoiding the Wave that Wasn’t There,” ATAP News, December 2016.)

The team studied this effect extensively and developed a simple model based on Snell-Descartes’ law that allowed them to finely predict the unphysical angular deviation of harmonics depending on the spatiotemporal resolution and the Maxwell solver used in the simulations.

The new model demonstrates that the mitigation of this numerical artifact with FDTD solvers mandates very high spatiotemporal resolution. This precludes realistic three-dimensional simulations even on the largest computers available at this time; the computing resources needed to arrive at a solution are unreasonable.

Maxwell solvers compared

Angularly resolved spectra for different Maxwell’s solvers in the frequency range of ωn/ω0 = 10 to 35, where ω0=2πc/λ0, λ0 is the laser wavelength, and c is the speed of light, for a spatial resolution of λ0/70 and a time resolution fixed by the Courant condition of the Maxwell field solver. The laser incidence is θi = 55◦. The white solid line is the curve expected from the refraction model. For two types of finite-difference solvers, as shown in (a) and (b), the numerical refraction index and angle of refraction are positive. For a pseudo-spectral solver with finite leapfrog time integration (PSTD), shown in (c), the numerical index and thus the refraction angle are negative. Panel (d) shows a dispersion-free spectrum obtained with the pseudo-spectral analytical time-domain (PSATD) solver.

A way around the problem

However, the new study also shows that nondispersive pseudospectral analytical time domain (PSATD) solvers can considerably reduce the spatiotemporal resolution required to mitigate this spurious deviation. Pseudospectral methods, which existed for decades, have enjoyed a renaissance in recent years as techniques for adapting them to highly parallel supercomputers were developed by ATAP researchers. PSATD solvers should enable accurate 3D modeling with a realistic amount of supercomputing time.

PSATD solvers have been recently benchmarked in 2D against Doppler harmonic generation experiments performed at CEA Saclay. These benchmarks demonstrated that PSATD solvers can reproduce experimental features with high fidelity and with much lower resource-to-solution than standard codes.

The benefits of these solvers have also been recently quantified for electrons emitted on plasma mirrors using 3D PIC simulations run at very large scale. These results showed that massively parallel PSTAD solvers require two orders of magnitude less resource-to-solution in 3D compared to standard codes.

To learn more…

G. Blaclard, H. Vincenti, R. Lehe, J.-L. Vay, “Pseudospectral Maxwell solvers for an accurate modeling of Doppler harmonic generation on plasma mirrors with Particle-In-Cell codes”, Phys. Rev. E 96, 033305 (11 September 2017), https://doi.org/10.1103/PhysRevE.96.033305.

A. Leblanc, S. Monchocé, H. Vincenti, S. Kahaly, J. -L. Vay, and F. Quéré, “Spatial properties of high-order harmonic beams from plasma mirrors: A ptychographic study”, Phys. Rev. Lett. 119, 155001 (13 October 2017), https://doi.org/10.1103/PhysRevLett.119.155001.

H. Vincenti, J.-L. Vay, “Ultrahigh-order Maxwell solver with extreme scalability for electromagnetic PIC simulations of plasmas,” submitted for refereed publication; http://arxiv.org/abs/1707.08500 (26 July 2017).

RECORD PERFORMANCE IN A HIGH-TEMPERATURE SUPERCONDUCTING MAGNET

The ATAP-led US Magnet Development Program (MDP) has set a current-density record for accelerator-style magnets made from high-temperature superconductor (HTS). The 3.3-tesla magnetic field quadrupled the HTS performance achievable just two years ago and was half again what could be achieved earlier this year.

Using a coil fabricated this summer by ATAP’s superconducting magnet program, the researchers built and tested a magnet made from Bi-2212 wire. The “racetrack” coil, made of 17-strand “Rutherford-style” cable, carried a record 8.2 kA while generating a peak field of 3.3 T, quadrupling performance of a dozen coils made before 2015 and representing a 60% increase over two coils made and tested in 2016 and earlier in 2017. The overall quench current density in the cable was 730 A/mm2 and the wire’s engineering current density was 930 A/mm2, which are practical current densities for applications.

Realizing the promise of HTS

High-temperature superconductor, whether used as inserts to augment traditional superconductors or (as in this case) as the principal conductor, has long offered tantalizing prospects to the developers of magnets for high-energy physics and other uses. The attraction is not their ability to superconduct at relatively high (though still cryogenic) temperatures—in fact, the work is done at the usual liquid-helium temperatures—but their high-field potential.

Increasing the field of an electromagnet calls for more current, but the wire and cable can only handle so much and remain superconductive. Traditional conductors, such as niobium-titanium (NbTi) and the higher-field niobium-three-tin (Nb3Sn) materials that are now coming into use, have a critical current density that decreases rapidly as magnetic field increases. The critical current density of Bi-2212 decreases much more slowly as the field goes up. The engineering current density of this coil is expected to remain above 500 A/mm2 even at 20 T — far above the magnetic fields achieved thus far in accelerator-style magnets.

Thanks to a multi-institutional, public/private sector team effort at all levels from materials through wire and cable fabrication, racetrack coil RC-05 achieved critical current an order of magnitude greater than its predecessors of several years ago and half again that of its immediate predecessors in the current effort.

This high critical current density, together with new magnet designs such as the canted cosine theta technology also being explored by MDP, makes it possible to envision 20-T-class accelerator magnets for future high-energy colliders, such as an energy upgrade of the Large Hadron Collider or the notional Future Circular Collider. “This is great news not only for high-energy physics, but for spinoff applications throughout science, wherever high-field magnets are needed,” said ATAP Division Director Wim Leemans. Examples include 25 T solenoids for >1 GHz nuclear magnetic resonance (NMR) magnets.

Potential long-term implications are numerous. “Our interests include expanding all the frontiers of what’s possible,” Leemans adds, “including the cost-effectiveness and feasibility frontiers as well as absolute performance. “One of our overarching interests is bringing the accelerator to the application, and higher fields can mean smaller machines as well as new capabilities.”

According to Prof. David Larbalestier, Chief Materials Scientist of the National High Magnetic Field Laboratory (NHMFL) at Florida State University and Director of its Applied Superconductivity Center, “The parameters and performance of this coil and solenoidal coils made at NHMFL show that Bi-2212 is now a high-field conductor, ready for magnets that can enable superconducting magnet applications impossible with any other superconductor.” Looking beyond high-energy physics, NHFML has an application interest of its own in mind: developing 1.3-1.6 GHz NMR magnets using this round, multifilamentary, twisted, fine filament and macroscopically isotropic wire.


Click for larger version
Engineering a top-performing superconducting magnet requires mastery of seemingly fractal detail, from the overall design down to the formulation of materials. Superconducting material (powdered, in this case) is made into filaments, which are formed into wire, which is then woven tightly into a flat cable.

Partnering is key to the field

The record-setting magnet was the work of many hands. Dr. Soren Prestemon, head of ATAP’s superconducting magnet program and Director of the U.S. Magnet Development Program and the Berkeley Center for Magnet Technology, described it as “an example of what is possible when U.S. national lab, universities, and private industry come together to push technologies.”

The LBNL-fabricated coil coil was heat-treated at the NHMFL. The wire was made by Bruker OST LLC in New Jersey from a precursor Bi-2212 powder, which in turn had been manufactured by nGimat LLC in Kentucky using an innovative nanospray technology. Bruker OST LLC and nGimat LLC were supported by the U.S. Department of Energy’s Small Business Innovation Research (SBIR) program, working closely with the teams at LBNL and NHMFL, under the framework of the MDP.

“I’m extremely grateful for the dedicated and talented teams at LBNL, NHMFL, Bruker OST, and nGimat,” said Dr. Tengming Shen, the ATAP researcher who led the effort. The record-setting achievement is a culmination of his Early Career Research Program (ECRP) work, which began in 2012.

LCLS-II UNDULATORS MOVE THROUGH PRODUCTION AS INJECTOR SOURCE PREPARES FOR MOVE TO SLAC

Measuring particles in the NEG/ion pump Berkeley Lab contributions to Linac Coherent Light Source II, a free-electron laser being built at SLAC by a partnership of SLAC and Berkeley Lab, Fermilab, Jefferson Lab, and Argonne, has seen continued progress in areas that include soft- and hard-X-ray FEL undulators and the VHF gun and low-energy beamline for the injector source.

SXR and HGVPU Undulator Production

Another pair of soft-X-ray undulators (SXRs) arrived at SLAC in September, making a total of six units delivered from vendors Keller Technology Corporation and Vacuumschmelze GmbH. The LBNL team continues to work with the vendors and with SLAC to monitor performance of the devices so that labor-intensive tuning is minimized and the installation schedule is maintained. To facilitate tuning, magnet modules are now delivered to LBNL for magnetic measurements and optimization before being shipped to a vendor for integration.

The HGVPUs (horizontal gap vertically polarized undulators) for the hard-X-ray beamline are moving through the production process as well. The first two sets of production magnetic modules built by Neorem Magnets Oy in Finland have been measured at LBNL and shipped to Keller Technology Corporation and Motion Solutions Co. LLC for integration of the magnetic and mechanical assemblies. These vendors are well advanced in their preparations and have assembly lines in place. A first article from one vendor is expected in late October, with the second following in November.

The pre-production HGVPU has undergone environmental testing and will be shipped to SLAC for long-term tests, which will exercise the movement of the adjustable gap and make periodic measurements to determine if the performance is impacted by the gap changes.

Two HGVPU production girders (blue) and one pair of strongbacks (long rectangular silver blocks atop the left girder) in the assembly area at Keller Technology await integration with the measured and optimized magnetic modules that will be shipped from LBNL. Our engineers have worked closely with each vendor and have visited their sites to assist in preparation and to verify that the processes developed here are being properly employed.

Injector Source Fabrication and Particle-Free Assembly

A vacuum leak found in the VHF gun assembly has been repaired, and the assembly has been fully re-cleaned using particle-free procedures and rebuilt; peripheral components are now being installed.

All components for the low-energy beamline downstream have been delivered to LBNL and subjected to particle-free cleaning. The buncher cavity and its power couplers have been tuned and matched, and final components are being mounted before bakeout.

A substantial documentation package describing the final as-built hardware is being finalized by the QA team, to be delivered together with the equipment. Delivery to SLAC, marking the completion of injector source production, is expected soon. The hardware will be installed in the SLAC linac enclosure in preparation for early injector commissioning, which is planned to start in January 2018. Members of the LBNL team will participate in the installation and commissioning.

The buncher cavity center wall and outer cells are shown at a vendor, ready for final brazing. The completed assembly is now at LBNL for frequency tuning, cleaning, and installation in the low-energy beamline. ATAP’s Fusion Science and Ion Beam Technology Program applied the titanium-nitride coating to this ceramic “break” or insulator in the integrating current transformer of the LCLS-II low-energy beamline. A combined nonevaporable getter (NEG) and ion pump for the VHF gun undergoes particulate measurement. Extreme cleanliness is a must to avoid potential contamination of the superconducting linac cavities in LCLS-II.

Gun Amplifier Production Making Progress

LBNL engineers again visited R&K Co. Ltd. in Fuji City, Japan, the vendor for the gun RF power amplifier. The meeting was to discuss technical details of the controls and operations of the amplifier, and to plan for acceptance tests to be completed in November.

PROJECT DIRECTOR’S UPDATE ON ALS-U

Based on an article in the September 27, 2017 issue of ALS News.

In the last year since the ALS Upgrade Project (ALS-U) received approval of mission need (CD-0) from the U.S. Department of Energy, I’m happy to report that we’ve made a lot of progress. I’d like to share some updates with you as well as offer opportunities for our users to engage in the next phases of the project.

The ALS-U Project team has been building momentum as we set up the project, develop the conceptual design, and carry out key R&D. A number of Berkeley Lab divisions are contributing to the efforts. Project team staff include members of ALS, Accelerator Technology and Applied Physics, Engineering, and Facilities, and we have received additional assistance from various operations divisions. The enthusiasm and support we’ve received from across Berkeley Lab for this project is a true testament of the “team science” spirit that E.O. Lawrence himself engendered and upon which the Lab was founded.

In addition to internal expertise, we’ve benefited from the input of external advisory committees. This past summer, we held the inaugural meetings of our Machine Advisory Committee (MAC), which is charged with providing advice on the technical design and R&D activities related to the accelerator systems and insertion devices, and Experimental Systems Advisory Committee (ESAC), which is providing advice on the technical design and R&D activities related to the beamlines. Overall, the feedback was very positive. Mentioned in particular were the quality of the team and the progress of the R&D as well as conceptual design. The ALS-U team received many detailed comments that will help strengthen our efforts moving forward. In addition, the ALS Scientific Advisory Committee (SAC) continues to provide important guidance on scientific directions.

In January, we held a workshop on “Solving Scientific Challenges with Coherent Soft X-Rays.” The event convened more than 170 U.S. and international scientists to discuss early science enabled by ALS-U. The recently released report contains a number of exciting opportunities presented by ALS-U’s new capabilities that address longstanding scientific challenges.

As we move into the next phases of the project, including the selection of new and rebuilt beamlines that will be part of the project scope, it will be critical to get input from ALS users. Over the next few months, we’ll be soliciting that input primarily through online user forums and crosscutting beamline reviews.

I look forward to continuing to work with you as we design and build the future of ALS.

NEWS IN BRIEF

ATAP’s Hand in Squeezing Microwaves for More-Sensitive Magnetic Resonance Spectroscopy

Conceptual illustration of magnetic resonance
A. Bienfait, Univ. Paris-Saclay
A multi-institutional effort led by Dr. Audrey Bienfait of the University of Paris-Saclay has demonstrated a “quantum squeeze” technique that games the Heisenberg uncertainty principle for more-sensitive magnetic resonance spectroscopy. The work is the subject of a new article in the journal Physical Review X.

Researchers led by Dr. Thomas Schenkel in ATAP’s Fusion Science and Ion Beam Technology Program, a co-author of the paper, conceived of, designed, and made the special spin material (bismuth-doped silicon-28, a silicon isotope with no nuclear spin of its own) that enabled this study.

To learn more…

MDP, BACI, AMP Refresh Web Presence

The US Magnet Development Program (MDP) announces the launch of its website, usmdp.lbl.gov, while the Accelerator Modeling Program and the Berkeley Accelerator Controls and Instrumentation Program — heirs to the legacy of the Center for Beam Physics — have pages of their own now on the ATAP website. We invite you to visit and learn more about their goals and achievements.

k-BELLA Workshop Report Available


The report of the Laser Technology for k-BELLA and Beyond Workshop is available online.

The topic of the workshop, held at LBNL May 9-11, was near- and long-term technology prospects for ultrafast lasers that could operate in the multi-kW to even tens-of-kW average power range. Such laser performance is needed for k-BELLA, further stepping stones to a laser-plasma accelerator relevant to high-energy physics, and spinoff benefits en route.

Memorandum of Understanding for High-Luminosity LHC Accelerator Upgrade Project

A formal Memorandum of Understanding between Fermilab and LBNL on the High-Luminosity LHC Accelerator Upgrade Project has been signed by both Laboratory Directors. The MOU defines the management structure, LBNL roles, and commitment to safety and quality.

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. The AUP was reviewed recently and given a Critical Decision 1/3a recommendation. The review 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.

Specific LBNL Statements of Work will be released by the AUP office. More than 12 years of work by ATAP as a partner in DOE-OHEP’s LHC Accelerator Research Program (LARP), with critical support and partnership with the Engineering Division, has resulted in two major roles in fabrication of interaction-region quadrupole magnets.

INCLUSION: A GAME EVERYBODY WINS
(but come score some points for yourself and our division anyway)


Inclusion Insights game cards can be posted as conversation starters, as Ina Reichel has done at her office
As a follow-up to the talks given by Dr. Steve Robbins on July 26-27, 2017, the Diversity and Inclusion Office (DIO) has launched a Labwide inclusion program called “Inclusion Starts with a Conversation.” DIO, along with the Diversity and Inclusion Council, invite all Lab employees to watch the inclusion videos and play the “Inclusion Insights” game. If you have attended one of Steve’s talks, you know that you can expect an experience that’s fun and and engaging as well as informative.

Each month, a set of short inclusion videos (2-8 minutes each; total no more than 10 to 15 minutes) will be announced in Today at Berkeley Lab and released on go.lbl.gov/inclusion. Accompanying each set of videos is a short game question that you can answer if you’ve watched the videos.

When you correctly answer the question, you’ll receive a playing card, which you are encouraged to display at your workstation. In keeping with the theme of “inclusion starts with a conversation,” when people ask you about the card, engage!

You get a point for each card, plus 5 bonus points if you were among the first 10 people to correctly answer each question in that round. Each Division at the Lab will also receive 10 bonus points for each facilitated group discussion that it hosts.

An Inclusion Conversation with LBNL Director Mike Witherell is the prize for the top ten point earners every 3 months (each individual can earn this prize only once). The overall top 3 point winners will also receive a prize, as will the Division with the most per-capita points. Ultimately, though, everybody who plays is a winner — and so is the whole Lab, because when more people know and care about inclusion, we all benefit.

ATAP will host a facilitated discussion for the November videos on Wednesday, November 8th from noon to 12:30 in the 71-264 conference room. Feel free to bring your lunch. If you would like to be added to the meeting on calendar, please email Ina Reichel (IReichel@lbl.gov). If your group would like to have an additional facilitated discussion either during one of its regular meetings or a special meeting, Dr. Reichel can arrange that as well.

Let’s start the conversation!

SAFETY: THE BOTTOM LINE

Wildfire or Other Emergency Evacuations: Would You Know What to Do?

Berkeley fire, 1923
Northside Berkeley, 9/17/1923: from a silent-era newsreel via Wikipedia.
The catastrophic fires in Napa and Sonoma Counties earlier this month brought up a question that should be on everyone’s mind: what should we do if there is a fire near Berkeley Lab?

Some of us went through this on August 2 during a precautionary evacuation. Those who lived and worked in these hills in 1991 — or 1970 — know that it is not an idle question. And then there was 1923, when a conflagration driven by the Diablo winds reached the intersection of Hearst and Shattuck. The Laboratory takes a variety of precautions to reduce its wildfire risk, and of course has its own fire department, but a “Diablo wind” is always a reminder that such threats are only mitigated, never eliminated.

Announcements of whether and how to evacuate

When a wildland fire is expected to impact the Lab, we will be notified through our Building Emergency Teams, building Public Address Systems, and the Lab Alert applications on our phones. The instructions may be to shelter in place or to evacuate the site, by vehicle or on foot.

Ready, steady, go

If there is time:
• Safely shut down your equipment.
• Gather your essential items (keys, cell phone, laptop, medications, wallet and ID, etc.). You may not be returning anytime soon — nor to an intact building.
• If you have a “go bag” for emergencies, ready with survival items such water, snacks, clothing, flashlight, etc., get it ready.

Leave only when your building is instructed to do so. This reduces traffic congestion. Evacuations may be called by zone (see the blue Site Map tab on the Emergency Guide flip charts) so know your zone! It is useful information in many emergencies. Shown below is a zone map with notes on principal ATAP buildings, taken from the Lab’s Emergency Guide.

emergency-zones map
Click for larger version
Zone 1 – 71 complex
Zone 2 – 88
Zone 3 – 46 complex, 47, 53, 58 complex, ALS buildings
Zone 4 – 77 and 77A

How to actually evacuate

• Bicycles can be a fast and efficient mode of evacuation.
• If you have a car, offer rides to others who do not have cars on site.
• As the fire approaches, the evacuation mode may change — be prepared to pull over, park , and continue on foot if necessary.
• You may be instructed to evacuate on foot. Have comfortable, sturdy walking shoes available (perhaps in your go-bag…)
• If you are unable to evacuate on foot, discuss this with your Building Emergency Team Leader in advance so that you can work out an assistance plan for your evacuation.

Be aware of multiple routes to exit LBNL and ways to get home.

What’s next?

There may be a designated off-site gathering area for people who cannot get home to meet and receive assistance.

After evacuating safely, contact your supervisor, if possible, and let him or her know that you are OK.

Monitor LabAlert, visit status.lbl.gov, or call 1-800-445-5830 for information about when it is safe to return.

Be In the Know in Emergencies with LabAlert

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.

ATAP News, August 2017

DIRECTOR’S CORNER


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.

LCLS-II CONTRIBUTIONS MOVE CLEANLY INTO PRODUCTION

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.

COMPACT, PRECISE BEAM COULD AID IN NUCLEAR SECURITY

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.

 

ATAP AND ENGINEERING’S QIANG DU AMONG LAB’S 5 ECRP SELECTEES

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).

 

 

ATAP’S TENGMING SHEN HONORED BY ICMC

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.

NEWS IN BRIEF

 

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.

REACHING OUT? HANDY HANDS-ON APPARATUS

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.

 

SAFETY: THE BOTTOM LINE

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.

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