Students make neutrons dance beneath Berkeley campus

Students make neutrons dance beneath Berkeley campus

September 11th, 2018

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In an underground vault enclosed by six-foot concrete walls and accessed by a rolling, 25-ton concrete-and-steel door, University of California, Berkeley, students are making neutrons dance to a new tune: one better suited to producing isotopes required for geological dating, police forensics, hospital diagnosis and treatment.

Dating and forensics rely on a spray of neutrons to convert atoms to radioactive isotopes, which betray the chemical composition of a substance, helping to trace a gun or reveal the age of a rock, for example. Hospitals use isotopes produced by neutron irradiation to kill tumors or pinpoint diseases like cancer in the body.

For these applications, however, only nuclear reactors can produce a strong enough spray of neutrons, and there are only two such reactors west of the Mississippi.

As an alternative, a team including UC Berkeley students has built a tabletop neutron source that would be relatively inexpensive to reproduce and eventually portable and also able to produce a narrower range of neutron energies, minimizing the production of unwanted radioactive byproducts.

“Any hospital in the country could have this thing, they could build it for a few hundred thousand dollars to make local, very short-lived medical isotopes — you could just run them up the elevator to the patient,” said Karl van Bibber, a UC Berkeley professor of nuclear engineering who oversees the students perfecting the device. “It has application in geochronology, neutron activation analysis for law enforcement agencies — when the FBI wants to determine the provenance of a sample as evidence, for example — neutron radiography, to look for cracks in aircraft parts. This is very compact, the size of a little convection oven; I think it’s great, we are excited about this.”

students with neutron generator

Graduate students Mauricio Ayllon Unzueta (left) and Jonathan Morrell adjust the high flux neutron generator in an underground vault at UC Berkeley. The aluminum vacuum chamber contains the deuterium plasma and the cathode target where the neutrons are generated via fusion. (UC Berkeley photo by Irene Yi)

UC Berkeley researchers have now demonstrated that the high flux neutron generator (HFNG) can produce “boutique” neutrons — neutrons within a very narrow range of energies — that can be used to accurately date fine-grained rocks nearly impossible to date by other radioisotope techniques. The study will be published this week in the journal Science Advances.

“This will expand the capability of dating fine-grained materials, like clay minerals associated with ore deposits, including gold, or lava flows,” said Paul Renne, a UC Berkeley professor-in- residence in the Department of Earth and Planetary Science and director of the Berkeley Geochronology Center. “This device might also let us look at the most primitive objects in our solar system — calcium/aluminum-rich inclusions found in certain types of meteorites — which are also very fine-grained.”

As they report in the new paper, the researchers used the neutron generator to determine the age of fine-grained lava from the 79 A.D. eruption of Vesuvius, which buried the Roman city of Pompeii. The date they calculated was as precise as the answer given by an exhaustive study in 1997 using state-of-the-art argon-argon dating of samples irradiated at a nuclear reactor.

“It’s making it possible to do things that were not possible otherwise,” Renne said.

The long road to desktop fusion

Renne has been searching for better ways to irradiate rock samples for decades and heard about one possible method from the late UC Berkeley nuclear engineering professor Stanley Prussin, who died in 2015. The technique involves the fusion of two deuterium atoms, which are isotopes of hydrogen, to produce helium-3 and one neutron. These neutrons have an energy — about 2.5 million electron volts — that is ideal for irradiating rocks to conduct argon-argon dating, one of the most precise methods in use today.

van Bibber and Renne near the vault

Nuclear engineer Karl van Bibber (left) and geochronologist Paul Renne (right) standing by the massive door to the vault housing the neutron generator. (UC Berkeley photo by Robert Sanders)

Argon-argon dating relies on the fact that about one in every 1,000 potassium atoms in rock is the radioactive isotope potassium-40, which decays to argon-40 with a half-life of more than a billion years. Using neutrons, scientists convert some of the stable potassium, potassium-39, to argon-39, then measure the ratio of Ar-40 to Ar-39 in the sample to calculate its age.

Rock samples must now be irradiated at nuclear reactors, but reactors produce very energetic neutrons that can knock argon atoms out of the sample — a particular problem for rocks with microscopic grains — and also produce unwanted radioactive elements. Both effects make age calculation more difficult.

The HFNG avoids both of these problems, because the neutrons are one-tenth the energy of those from a nuclear reactor and have a narrower range of energies, while still maintaining a high flux of neutrons.

“Eliminating the recoil issue, plus reduction of interfering reactions, is huge,” Renne said. “But the radiological aspects are also improved.”

“The beauty of this thing, we realized, is that you don’t have this thing spewing neutrons everywhere and creating a radiological issue,” added van Bibber, who is the Shankar Sastry Chair of Leadership and Innovation. “You’re actually having a modest number of neutrons, but by getting the target close to the point source — the thing that matters — the neutron flux at the sample is very high.”

The first device to create neutrons via deuterium-deuterium (D-D) fusion was designed 10 years ago by Renne’s team, which included plasma physicist Ka-Ngo Leung, formerly of Lawrence Berkeley National Laboratory (Berkeley Lab). But their prototype languished until van Bibber took an interest in 2012, shortly after his appointment as chair of UC Berkeley’s Department of Nuclear Engineering. To house the fusion generator, van Bibber took over a concrete vault formerly used for experiments conducted with the campus’s nuclear reactor, which used to sit under what is now Soda Hall — though it sits in a large underground room that is part of the basement of Etcheverry Hall — until the reactor closed in 1987 and was removed.

a cutaway view of the neutron generator

This cutaway of the high flux neutron generator shows the two chambers (bronze) where the deuterium is heated to 50,000 C, creating a plasma of ionized deuterium. A 100,000-volt charge at the extraction plate accelerates the ions toward the target, which contains more deuterium atoms. When two deuterium atoms fuse, they produce a neutron, which irradiates a sample placed nearby. The shroud prevents excessive heating from backstreaming electrons.

The generator employs about 100,000 volts to accelerate ionized deuterium atoms toward a metal cathode made of titanium. The deuterium accumulates on the cathode in a thin layer that then serves as a target for other incoming ions. When colliding deuterons fuse, a neutron is produced in a broad beam that irradiates the sample located about a third of an inch away.

Over the years, van Bibber enlisted many undergraduates, graduate students and postdoctoral fellows to help make the neutron generator a reality. One of them, transfer student Max Wallace, a rising senior interested in nuclear forensics, was amazed at the access he had to such a machine.

“It’s rare to be able to work with radioisotopes as an undergraduate,” said the former software engineer. “I learned to do so much late at night, wearing gloves and goggles to measure the radiation, taking samples, doing safety checks and running the software. Really, I’d learn something in my nuclear physics class and then come down here to work on a direct application of it.”

For Mauricio Ayllon Unzueta, a fourth-year graduate student in nuclear engineering, the experience he obtained in helping to perfect the neutron generator led directly to a new project at Berkeley Lab: designing a variant of the HFNG that could be taken into the field to do neutron activation of soils to measure carbon content — a key piece of information if society hopes to sequester carbon in soils to mitigate climate change.

“Through three generations of graduate students, we turned it from something which barely worked into a high performing neutron generator,” van Bibber said.

Daniel Rutte, a UC Berkeley postdoctoral researcher in geology working with Renne and BGC lab manager Tim Becker, played a critical role in designing and conducting the first dating experiment, according to Renne.

“Daniel was literally the key player in demonstrating that this would work for Ar-Ar geochronology,” he said.

Rutte’s goal is to develop new methods and instruments to better understand Earth processes, in particular the deformation of the Earth’s crust, which occurs by slow creep or rapid rupture resulting in earthquakes.

“To understand long-term crustal deformation, I date old ruptures preserved in the rock record,” Rutte said. “The neutron generator will aid progress in this field by expanding the range of materials we can date.”

Karl van Bibber adjusting neutron generator

Karl van Bibber examining the high flux neutron generator in an underground concrete vault that blocks X-rays produced when the experiment is running. (UC Berkeley photo by Robert Sanders)

With ongoing student help, van Bibber and Renne expect to be able to make the neutron generator more compact and to produce a more intense spray of neutrons, making it more broadly useful for geochronology, as well as for other specialized uses. Researchers at UC Berkeley’s Space Sciences Laboratory have already shown interest in using these neutrons to test electronic hardware to determine how it will survive in the radioactive environment of space. Higher energy neutrons could be used for neutron radiography, which can complement X-ray radiography in imaging the interior of dense objects, like metals.

“The purpose all along had been to test Paul’s dream of whether we could use a very compact, low-voltage device to do neutron irradiation,” van Bibber said. “We’ve now shown that any university can have a neutron source for doing the argon-argon dating technique.”

Co-authors of the paper with Renne, van Bibber, Wallace and Ayllon are former postdoctoral researcher and first author Daniel Rutte, now at the University of Bonn in Germany; students Jonathan Morrell, Jon Batchelder, Su-Ann Chong, Will Heriot, Angel Marcial, Charles Johnson, Graham Woolley and Parker Adams and electrical engineer Jay James, all of UC Berkeley; Liqiang Qi, Jonathan Wilson and Mathieu Lebois of the Institut de Physique Nucléaire d’Orsay in France; Tim Becker of BGC; and Lee Bernstein of Berkeley Lab. The work was funded in part by the National Science Foundation (EAR-0960138).

Nuclear Innovation Bootcamp 2019

Nuclear Innovation Bootcamp 2019

August 30, 2019

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This year the Nuclear Innovation Bootcamp took place in Paris (Berkeley has hosted for the past 3 years). However, with the support of the Nuclear Energy Agency and Atomic Energy Commission, it became an international effort.
The Nuclear Innovation Bootcamp 2019 is a two week intense program consisting of presentations, high level (energy context, development strategy of companies in the sector, practices outside the industry, etc.) technical (nuclear costs, materials of the future, etc.), and creativity sessions or entrepreneurial modules (business plan, how to get financed, how to pitch well, etc.) They're also 28 participants, selected from more than 150 applications, 50 speakers, 30 mentors, and 10 organizers.
For more information please see the Indonesian or French article (Note: use Google Chrome to translate the entire webpage).

Ultra-selective ligand-driven separation of strategic actinides

Ultra-selective ligand-driven separation of strategic actinides

Gauthier J.-P. Deblonde, Abel Ricano & Rebecca J. Abergel

Metal ion separations are critical to numerousfields, including nuclear medicine, wasterecycling, space exploration, and fundamental research. Nonetheless, operational conditionsand performance are limited, imposing compromises between recovery, purity, and cost.Siderophore-inspired ligands show unprecedented charge-based selectivity and compatibilitywith harsh industry conditions, affording excellent separation efficiency, robustness andprocess control. Here, we successfully demonstrate a general separation strategy on threedistinct systems, for Ac, Pu, and Bk purification. Separation factors (SF) obtained with modelcompound 3,4,3-LI(1,2-HOPO) are orders of magnitude higher than with any other ligandcurrently employed: 106between Ac and relevant metal impurities, and over 108for redox-free Pu purification against uranyl ions and trivalent actinides orfission products. Finally,a one-step separation method (SF > 3 × 106and radiopurity > 99.999%) enables the isolationof Bk from adjacent actinides andfission products. The proposed approach offers a paradigmchange for the production of strategic elements.

Full article: https://www.nature.com/articles/s41467-019-10240-x.epdf?author_access_token=0bMOSggKFWk-rMDZvwdF2dRgN0jAjWel9jnR3ZoTv0P0WhESc3vqzmdSObNwVAJ7bXq0YKzQz36fG4_Y5IlOsK_j-V9a-JVsGkwd7kEtRF1yVrSdsyBsGYkP0thD-KdyOSUv_W1FK7bTn9S1JHPEbg==

Separation Anxiety No More: A Faster Technique to Purify Elements

Separation Anxiety No More: A Faster Technique to Purify Elements

June 4, 2019

Workforce Development & Education Intern and Mentor Spring 2017 3/20/2017. - Abel Ricano, intern - Rebecca Abergel and Gauthier Deblonde, mentors - Chemical Sciences. Science Undergraduate Laboratory Internship (SULI). Supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS).

The actinides – those chemical elements on the bottom row of the periodic table – are used in applications ranging from medical treatments to space exploration to nuclear energy production. But purifying the target element so it can be used, by separating out contaminants and other elements, can be difficult and time-consuming.

Now researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a new separation method that is vastly more efficient than conventional processes, opening the door to faster discovery of new elements, easier nuclear fuel reprocessing, and, most tantalizing, a better way to attain actinium-225, a promising therapeutic isotope for cancer treatment.

The research, “Ultra-Selective Ligand-Driven Separation of Strategic Actinides,” has been published in the journal Nature Communications. The authors are Gauthier Deblonde, Abel Ricano, and Rebecca Abergel of Berkeley Lab’s Chemical Sciences Division. “The proposed approach offers a paradigm change for the production of strategic elements,” the authors wrote.

“Our proposed process appears to be much more efficient than existing processes, involves fewer steps, and can be done in aqueous environments, and therefore does not require harsh chemicals,” said Abergel, who is lead of Berkeley Lab’s Heavy Element Chemistry group and also an assistant professor in UC Berkeley’s nuclear engineering department. “I think this is really important and will be useful for many applications.”

Berkeley Lab is one of a handful of institutions around the world studying the nuclear and chemical properties of the heaviest elements. Most of them were, in fact, discovered at Berkeley Lab in the last century. Abergel’s group has previously published discoveries on berkelium and plutonium and treatments for radioactive contamination.

Abergel noted that the new separation method achieves separation factors that are many orders of magnitude higher than current state-of-the-art methods. The separation factor is a measure of how well an element can be separated from a mixture. “The higher the separation factor, the fewer contaminants there are,” she said. “Usually when you purify an element you’ll go through the cycle many times to reduce contaminants.”

With a higher separation factor, fewer steps and less solvents are needed, making the process faster and more cost-effective. For example, the scientists demonstrated for one of the three systems they purified that they could reduce the process from 25 steps to just two steps.

The Berkeley Lab researchers demonstrated their method first on actinium-225, an isotope of actinium that has shown very promising radio-therapeutic applications. It works by killing cancer cells but not healthy cells, through targeted delivery.

DOE’s Isotope Program is actively working on ramping up production of actinium-225 throughout the complex of national laboratory-based accelerators. This new separation method could be an alternative to chemical processes currently under development. “With any production process, you need to purify the final isotope,” Abergel said. “Our method could be used right after production, before distribution.”

The two other actinides purified in this study were plutonium and berkelium. An isotope of plutonium, plutonium-238, is used for power generation in robots being sent to explore Mars. Plutonium isotopes are also present in waste generated at nuclear power plants, where they must be separated out from the uranium in order to recycle the uranium.

Lastly, berkelium is important for fundamental science research. One of its uses is as a target for discovery of new elements.

The process relies on the unprecedented ability of synthetic ligands – small molecules that bind metal atoms – to be highly selective in binding to metallic cations (positive ions) based on the size and charge of the metal.

The next step, said Abergel, is to explore using the process on other medical isotopes. “Based on what we’ve seen, this new method can really be generalized, as long as we have different charges on the metals we want to separate,” she said. “Having a good purification process available could make everything easier in terms of post-production processing and availability.”

The study was funded by the DOE Office of Science. Ricano was previously a participant in DOE’s Science Undergraduate Laboratory Internship (SULI) program at Berkeley Lab.

# # #

Founded in 1931 on the belief that the biggest scientific challenges are best addressed by teams, Lawrence Berkeley National Laboratory and its scientists have been recognized with 13 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environmental solutions, create useful new materials, advance the frontiers of computing, and probe the mysteries of life, matter, and the universe. Scientists from around the world rely on the Lab’s facilities for their own discovery science. Berkeley Lab is a multiprogram national laboratory, managed by the University of California for the U.S. Department of Energy’s Office of Science.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

Source: https://newscenter.lbl.gov/2019/06/04/separation-anxiety-no-more-a-faster-technique-to-purify-elements/

Berkeley Students Win Awards at 2019 ANS Conference

Berkeley Students Win Awards at 2019 ANS Conference

Wednesday, April 10th, 2019

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Undergraduate students Andrew Dong and Emily Vu won awards for their presentations at the American Nuclear Society Conference this past week, April 4-6, held in Richmond, Virginia.
Andrew Dong was awarded Best Presentation in Materials Science and Technology. While Emily Vu took home Best Presentation in Mathematics and Computation.

See here for the full list of award winners.

Great job Andrew and Emily, you make us proud!

Visiting Student Markus Alfreider wins 3rd place in Poster Contest

Visiting Student Markus Alfreider Wins 3rd Place in Poster Contest

April 2, 2019

TMS2019 Poster Certificate Third Place - Mechanical Behavior

Markus Alfreider is a visiting student from Austria, funded through the Marshall Plan fellowship. He won 3rd place in the TMS 2019 poster award in "Mechanical Behavior Related to Interface Physics III". The contest took place in San Antonio, Texas. This work was a collaboration between Leoben and Berkeley.

Congratulations, Markus!

CSS 2019 Graduate Student Fellowship Announcement

CCS 2019 Graduate Student Fellowship Announcement

March 12, 2019

The Center for Chinese Studies offers annual competitive fellowships for continuing graduate students in Chinese studies. Applications must be received by email by April 1, 2019. Late applications will not be considered. 
 
Applications and more information here: 

  • CCS Language Study Grants
  • Dissertation Writing fellowships 
  • MA Student Fellowships
  • Republic of China East Asian Fellowships
  • CCS Summer Research Grants
  • Chu Fellowships
  • Liu Graduate Research Fellowships
  • Joseph R. Levenson Chinese Studies Awards
  • Elvera Kwang Siam Lim Fellowship in Chinese Studies
  • Pamela and Kenneth Fong Graduate Student Fellowships

Students may apply for more than one CCS award but may apply to only one of the five Center/Institute competitions, so should carefully consider which one best suits their needs.

Graduate students applying for these awards should be registered at Berkeley or on approved travel status during the award period.

Please contact ccs@berkeley.edu with questions.

Out for Undergrad Application Round One is Open

Out for Undergrad Application Round One is Open

March 11th, 2019

If you're not familiar with Out for Undergrad (O4U) or the O4U Engineering Conference, you can learn more about it on the website here: https://www.outforundergrad.org/. To keep it short and sweet, it is a weekend-long professional development conference for high achieving, high potential LGBTQ+ undergraduate students who are studying engineering or interested in going into engineering.

This year’s O4U Engineering Conference will be held at Boston Scientific in Minneapolis, Minnesota from September 27th to September 29th. The application deadline for round one admissions is March 23rd, 2019 at 11:59 PM (EST).

Students are admitted to attend the conference on a rolling basis. Flights and hotels are covered entirely by O4U, so if students are admitted from your college/university, they will only have to pay the $90 registration fee. We also offer fee waivers, discounts, and payment plans to students who are not able to afford the registration fee.

If there are any additional questions/concerns, please feel free to reach out to the O4U Engineering Admissions Team at O4UEngineeringAdmissions@outforundergrad.org.

NE Faculty Rebecca Abergel and BioActinide group highlighted in C&EN

NE Faculty Rebecca Abergel and BioActinide group highlighted in C&EN

March 4th, 2019

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NE faculty Rebecca Abergel and her BioActinide group were recently highlighted in an article on Chemical and Engineering News. To read the article, please click here: https://cen.acs.org/physical-chemistry/periodic-table/IYPT-Chemists-explore-periodic-tables-actinide/97/i9

 

To learn more about the BioActinide group at Lawrence Berkeley National Laboratory, click here: http://actinide.lbl.gov/gtsc/BioAn/index.html