From DOE’s Argonne National Laboratory (US) : “Scientists recreate cosmic reactions to unlock astronomical mysteries”

Argonne Lab

From DOE’s Argonne National Laboratory (US)

September 28, 2021
J.D. Amick

Experiments will give scientists a closer look at how exploding stars create world’s heaviest elements.

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An interior view of SOLARIS and the accelerator and detectors at the rear. (Image by Argonne National Laboratory.)

How do the chemical elements, the building blocks of our universe, get built? This question has been at the core of nuclear physics for the better part of a century.

At the beginning of the 20th century, scientists discovered that elements have a central core or nucleus. These nuclei consist of various numbers of protons and neutrons.

Now, scientists at Michigan State University (US)’s Facility for Rare Isotope Beams (FRIB) have built and tested a device that will allow pivotal insights into heavy elements, or elements with very large numbers of protons and neutrons. Ben Kay, physicist at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, led this effort. FRIB is a DOE Office of Science User Facility.

Kay and his team have completed their first experiment using the device, called SOLARIS, which stands for Solenoid Spectrometer Apparatus for Reaction Studies. Planned experiments will reveal information about nuclear reactions that create some of the heaviest elements in our world, ranging from iron to uranium.

Also planned are experiments with exotic isotopes. Isotopes are elements that share the same number of protons but have different numbers of neutrons. Scientists refer to certain isotopes as exotic because their ratios of protons to neutrons differ from those of typically stable or long-lived isotopes that occur naturally on Earth. Some of these unstable isotopes play an essential role in astronomical events.

“Exploding stars, the merger of giant collapsed stars, we are now learning details about the nuclear reactions at the heart of these events,” said Kay. ​“With SOLARIS, we are able to recreate those reactions here, on Earth, to see them for ourselves.”

The new device follows in the footsteps of HELIOS, the Helical Orbit Spectrometer, at Argonne. Both use similarly repurposed superconducting magnets from a magnetic resonance imaging (MRI) machine like that found in hospitals. In both, a beam of particles is shot at a target material inside of a vacuum chamber. When the particles collide with the target, transfer reactions occur. In such reactions, neutrons or protons are either removed or added from nuclei, depending on the particles, and their energies, used in the collision.

“By recording the energy and angle of the various particles that are released or deflected from the collisions, we are able to gather information about the structure of the nuclei in these isotopes,” said Kay. ​“The innovative SOLARIS design provides the necessary resolution to enhance our understanding of these exotic nuclei.”

What makes SOLARIS truly unique is it can function as a dual-mode spectrometer, meaning it can make measurements with either high or very low intensity beams. ​“SOLARIS can operate in these two modes,” explained Kay. ​“One uses a traditional silicon detector array in a vacuum. The other uses the novel gas-filled target of the Active-Target Time-Projection Chamber at Michigan State, led by SOLARIS team member and FRIB senior physicist Daniel Bazin. This first experiment tested the AT-TPC.” The AT-TPC enables scientists to use weaker beams and still collect results with the needed high accuracy.

The AT-TPC is essentially a large chamber filled with a gas that serves as both the target for the beam and the detector medium. This differs from the traditional vacuum chamber that uses a silicon detector array and a separate, thin, solid target.

“By filling the chamber with gas, you are ensuring that the fewer, larger particles from the low-intensity beam will make contact with the target material,” said Kay. In that way, the scientists can then study the products from those collisions.

The team’s first experiment, led by research associate Clementine Santamaria of FRIB, examined the decay of oxygen-16 (the most common isotope of oxygen on our planet) into much smaller alpha particles. In particular, the eight protons and eight neutrons in oxygen-16 nuclei break up into a total of four alpha particles, each consisting of two protons and two neutrons.

“By determining how oxygen-16 decays like this, comparisons can be made to that of the ​‘Hoyle state,’ an excited state of a carbon isotope that we believe plays a key role in the production of carbon in stars,” explained Kay.

Kay and his team recorded over two million reaction events during this experiment and observed several instances of the decay of oxygen-16 into alpha particles.

The dual functionality of SOLARIS will allow for an even broader range of nuclear reaction experiments than before, and give scientists new insights into some of the greatest mysteries of the cosmos.

See the full article here .

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DOE’s Argonne National Laboratory (US) seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their is a science and engineering research national laboratory operated by UChicago Argonne LLC for the United States Department of Energy. The facility is located in Lemont, Illinois, outside of Chicago, and is the largest national laboratory by size and scope in the Midwest.

Argonne had its beginnings in the Metallurgical Laboratory of the University of Chicago, formed in part to carry out Enrico Fermi’s work on nuclear reactors for the Manhattan Project during World War II. After the war, it was designated as the first national laboratory in the United States on July 1, 1946. In the post-war era the lab focused primarily on non-weapon related nuclear physics, designing and building the first power-producing nuclear reactors, helping design the reactors used by the United States’ nuclear navy, and a wide variety of similar projects. In 1994, the lab’s nuclear mission ended, and today it maintains a broad portfolio in basic science research, energy storage and renewable energy, environmental sustainability, supercomputing, and national security.

UChicago Argonne, LLC, the operator of the laboratory, “brings together the expertise of the University of Chicago (the sole member of the LLC) with Jacobs Engineering Group Inc.” Argonne is a part of the expanding Illinois Technology and Research Corridor. Argonne formerly ran a smaller facility called Argonne National Laboratory-West (or simply Argonne-West) in Idaho next to the Idaho National Engineering and Environmental Laboratory. In 2005, the two Idaho-based laboratories merged to become the DOE’s Idaho National Laboratory.

What would become Argonne began in 1942 as the Metallurgical Laboratory at the University of Chicago, which had become part of the Manhattan Project. The Met Lab built Chicago Pile-1, the world’s first nuclear reactor, under the stands of the University of Chicago sports stadium. Considered unsafe, in 1943, CP-1 was reconstructed as CP-2, in what is today known as Red Gate Woods but was then the Argonne Forest of the Cook County Forest Preserve District near Palos Hills. The lab was named after the surrounding forest, which in turn was named after the Forest of Argonne in France where U.S. troops fought in World War I. Fermi’s pile was originally going to be constructed in the Argonne forest, and construction plans were set in motion, but a labor dispute brought the project to a halt. Since speed was paramount, the project was moved to the squash court under Stagg Field, the football stadium on the campus of the University of Chicago. Fermi told them that he was sure of his calculations, which said that it would not lead to a runaway reaction, which would have contaminated the city.

Other activities were added to Argonne over the next five years. On July 1, 1946, the “Metallurgical Laboratory” was formally re-chartered as Argonne National Laboratory for “cooperative research in nucleonics.” At the request of the U.S. Atomic Energy Commission, it began developing nuclear reactors for the nation’s peaceful nuclear energy program. In the late 1940s and early 1950s, the laboratory moved to a larger location in unincorporated DuPage County, Illinois and established a remote location in Idaho, called “Argonne-West,” to conduct further nuclear research.

In quick succession, the laboratory designed and built Chicago Pile 3 (1944), the world’s first heavy-water moderated reactor, and the Experimental Breeder Reactor I (Chicago Pile 4), built-in Idaho, which lit a string of four light bulbs with the world’s first nuclear-generated electricity in 1951. A complete list of the reactors designed and, in most cases, built and operated by Argonne can be viewed in the, Reactors Designed by Argonne page. The knowledge gained from the Argonne experiments conducted with these reactors 1) formed the foundation for the designs of most of the commercial reactors currently used throughout the world for electric power generation and 2) inform the current evolving designs of liquid-metal reactors for future commercial power stations.

Conducting classified research, the laboratory was heavily secured; all employees and visitors needed badges to pass a checkpoint, many of the buildings were classified, and the laboratory itself was fenced and guarded. Such alluring secrecy drew visitors both authorized—including King Leopold III of Belgium and Queen Frederica of Greece—and unauthorized. Shortly past 1 a.m. on February 6, 1951, Argonne guards discovered reporter Paul Harvey near the 10-foot (3.0 m) perimeter fence, his coat tangled in the barbed wire. Searching his car, guards found a previously prepared four-page broadcast detailing the saga of his unauthorized entrance into a classified “hot zone”. He was brought before a federal grand jury on charges of conspiracy to obtain information on national security and transmit it to the public, but was not indicted.

Not all nuclear technology went into developing reactors, however. While designing a scanner for reactor fuel elements in 1957, Argonne physicist William Nelson Beck put his own arm inside the scanner and obtained one of the first ultrasound images of the human body. Remote manipulators designed to handle radioactive materials laid the groundwork for more complex machines used to clean up contaminated areas, sealed laboratories or caves. In 1964, the “Janus” reactor opened to study the effects of neutron radiation on biological life, providing research for guidelines on safe exposure levels for workers at power plants, laboratories and hospitals. Scientists at Argonne pioneered a technique to analyze the moon’s surface using alpha radiation, which launched aboard the Surveyor 5 in 1967 and later analyzed lunar samples from the Apollo 11 mission.

In addition to nuclear work, the laboratory maintained a strong presence in the basic research of physics and chemistry. In 1955, Argonne chemists co-discovered the elements einsteinium and fermium, elements 99 and 100 in the periodic table. In 1962, laboratory chemists produced the first compound of the inert noble gas xenon, opening up a new field of chemical bonding research. In 1963, they discovered the hydrated electron.

High-energy physics made a leap forward when Argonne was chosen as the site of the 12.5 GeV Zero Gradient Synchrotron, a proton accelerator that opened in 1963. A bubble chamber allowed scientists to track the motions of subatomic particles as they zipped through the chamber; in 1970, they observed the neutrino in a hydrogen bubble chamber for the first time.

Meanwhile, the laboratory was also helping to design the reactor for the world’s first nuclear-powered submarine, the U.S.S. Nautilus, which steamed for more than 513,550 nautical miles (951,090 km). The next nuclear reactor model was Experimental Boiling Water Reactor, the forerunner of many modern nuclear plants, and Experimental Breeder Reactor II (EBR-II), which was sodium-cooled, and included a fuel recycling facility. EBR-II was later modified to test other reactor designs, including a fast-neutron reactor and, in 1982, the Integral Fast Reactor concept—a revolutionary design that reprocessed its own fuel, reduced its atomic waste and withstood safety tests of the same failures that triggered the Chernobyl and Three Mile Island disasters. In 1994, however, the U.S. Congress terminated funding for the bulk of Argonne’s nuclear programs.

Argonne moved to specialize in other areas, while capitalizing on its experience in physics, chemical sciences and metallurgy. In 1987, the laboratory was the first to successfully demonstrate a pioneering technique called plasma wakefield acceleration, which accelerates particles in much shorter distances than conventional accelerators. It also cultivated a strong battery research program.

Following a major push by then-director Alan Schriesheim, the laboratory was chosen as the site of the Advanced Photon Source, a major X-ray facility which was completed in 1995 and produced the brightest X-rays in the world at the time of its construction.

On 19 March 2019, it was reported in the Chicago Tribune that the laboratory was constructing the world’s most powerful supercomputer. Costing $500 million it will have the processing power of 1 quintillion flops. Applications will include the analysis of stars and improvements in the power grid.

With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

About the Advanced Photon Source

The U. S. Department of Energy Office of Science’s Advanced Photon Source (APS) at Argonne National Laboratory is one of the world’s most productive X-ray light source facilities. The APS provides high-brightness X-ray beams to a diverse community of researchers in materials science, chemistry, condensed matter physics, the life and environmental sciences, and applied research. These X-rays are ideally suited for explorations of materials and biological structures; elemental distribution; chemical, magnetic, electronic states; and a wide range of technologically important engineering systems from batteries to fuel injector sprays, all of which are the foundations of our nation’s economic, technological, and physical well-being. Each year, more than 5,000 researchers use the APS to produce over 2,000 publications detailing impactful discoveries, and solve more vital biological protein structures than users of any other X-ray light source research facility. APS scientists and engineers innovate technology that is at the heart of advancing accelerator and light-source operations. This includes the insertion devices that produce extreme-brightness X-rays prized by researchers, lenses that focus the X-rays down to a few nanometers, instrumentation that maximizes the way the X-rays interact with samples being studied, and software that gathers and manages the massive quantity of data resulting from discovery research at the APS.

With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

About the Advanced Photon Source

The U. S. Department of Energy Office of Science’s Advanced Photon Source (APS) at Argonne National Laboratory is one of the world’s most productive X-ray light source facilities. The APS provides high-brightness X-ray beams to a diverse community of researchers in materials science, chemistry, condensed matter physics, the life and environmental sciences, and applied research. These X-rays are ideally suited for explorations of materials and biological structures; elemental distribution; chemical, magnetic, electronic states; and a wide range of technologically important engineering systems from batteries to fuel injector sprays, all of which are the foundations of our nation’s economic, technological, and physical well-being. Each year, more than 5,000 researchers use the APS to produce over 2,000 publications detailing impactful discoveries, and solve more vital biological protein structures than users of any other X-ray light source research facility. APS scientists and engineers innovate technology that is at the heart of advancing accelerator and light-source operations. This includes the insertion devices that produce extreme-brightness X-rays prized by researchers, lenses that focus the X-rays down to a few nanometers, instrumentation that maximizes the way the X-rays interact with samples being studied, and software that gathers and manages the massive quantity of data resulting from discovery research at the APS.

Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science

Argonne Lab Campus