News Article | October 23, 2015
Two large science experiments head a wish list drawn up by US nuclear physicists for the next decade: a quest to uncover the nature of neutrinos and a particle collider to study the forces that bind quarks. The big-ticket items, each of which would cost hundreds of millions of dollars, are among the top priorities highlighted by the Nuclear Science Advisory Committee (NSAC) on 15 October. Every 5–7 years, this panel of high-level nuclear physicists presents a long-term plan to the US Department of Energy and National Science Foundation, after consulting the US nuclear-physics community. The agenda assumes that US funding for nuclear science will increase by 1.6% per year above inflation — a realistic scenario, says NSAC chair Donald Geesaman, a physicist at Argonne National Laboratory in Illinois. “We have exciting science to do, and we are not asking for large increases,” he says. The neutrino experiment, construction of which could begin by the end of the decade, would search for a theorized rare form of radioactive decay in which two identical neutrinos annihilate one another — an event that would imply that neutrinos are their own anti-particles. It could provide a way to measure the tiny mass of neutrinos and help to explain why the Universe has lots of matter but almost no antimatter. Experiments around the world using materials such as liquid xenon have failed to detect the event, known as neutrinoless double β decay. One of the largest is the Enriched Xenon Observatory-200 (EXO-200) experiment, which uses 200 kilograms of xenon as a detector deep below the desert outside Carlsbad, New Mexico. But the NSAC report says that an experiment using a tonne or more of material — about ten times more than any previous attempt — could either find or rule out the phenomenon. Confirming neutrinoless double β decay "would in one stroke add lots of stuff to our knowledge of the natural world," says Giorgio Gratta, a physicist at Stanford University in California, and a former spokesperson for EXO-200. Another priority, on which Nature reported in May, is a particle accelerator that would collide electrons with protons or heavy ions to investigate gluons, which carry the force that binds quarks. But construction would have to wait until the 2020s because NSAC’s top priority is to complete and maintain existing facilities, such as the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in Upton, New York. RHIC faced closure two years ago, but an improved budgetary position means it can now be sustained into the next decade. Although a more powerful heavy-ion experiment is housed in the Large Hadron Collider at CERN, Europe’s particle-physics laboratory in Geneva, Switzerland, researchers say that RHIC still has important science to do. Both experiments melt atomic nuclei together into a liquid-like soup of quarks and gluons, but each looks at different energy scales. “Collisions at lower energy create a very different kind of matter,” says Jamie Nagle, a physicist at the University of Colorado at Boulder who works on RHIC. NSAC also wants to continue support for two other leading US facilities: the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson National Laboratory in Newport News, Virginia, and the planned US$700 million construction of the Facility for Rare Isotope Beams (FRIB) at Michigan State University in East Lansing. Its final priority is to increase funding for small- and medium-scale projects through mechanisms such as the National Science Foundation’s Major Research Instrumentation programme, which supplies scientific equipment to universities. “All recommendations and priorities were agreed on by consensus,” says Geesaman.
News Article | October 26, 2016
List of discoveries shows US contributions have declined, but Japanese, Russian and European work is on the rise. When it comes to discovering nuclear isotopes, retired physicist Gottfried Münzenberg is top, with 222. His colleague Hans Geissel, from the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, is next with 211. Then comes Francis Aston, the British chemist who won the 1922 Nobel Prize in Chemistry, with 207. These provisional rankings have been assembled by Michael Thoennessen, a physicist at the National Superconducting Cyclotron Laboratory at Michigan State University in East Lansing. With the help of several undergraduate students, he has assembled a database of the almost 3,100 known nuclear isotopes — atoms that share the same number of protons but have varying numbers of neutrons. He lists the discovery of each by researcher, the lab at which they worked and the method by which they produced the isotope. The vast majority of these isotopes only exist naturally for fleeting moments inside stars, formed during the production of heavy elements. They never exist on Earth at all, except for a few nanoseconds in elite nuclear-physics labs. The International Union of Pure and Applied Chemistry, headquartered in Zurich, Switzerland, assigns the official credit for discovering elements, but Thoennessen is now doing the same for all the isotopes of those elements. "I don't think it matters so much who gets the credit, but historically it's important to identify which countries and labs are driving the field," he says. The database lets Thoennessen rank labs as well as people, and to track how different countries' rising and falling investments in nuclear technology have affected where and how isotopes are discovered (Click here for an animated chart of known isotopes that shows how many were found in quick succession with each new wave of technology). Top of the lab list is Lawrence Berkeley National Laboratory in Berkeley, California, with 634 isotopes. GSI Darmstadt is second with 368; the University of Cambridge, UK, is third with 222, its discoveries made mostly in the days of Aston; and the Joint Institute for Nuclear Research in Dubna, Russia, is fourth with 215. Berkeley may reign supreme in terms of sheer numbers, but the trend over time tells a different story. In the 1980s and 1990s the lab failed to upgrade its equipment and so fell behind other labs. It also lost some credibility in 2002, when allegations surfaced that physicist Victor Ninov had faked the discovery of elements 116 and 118 there. These days, most new finds come from GSI Darmstadt, Dubna and other locations, such as the Radioactive Isotope Beam Factory(RIBF) in Wako, part of Japan's RIKEN national network of labs. Although the decline of Berkeley means that the United States is losing ground, in the longer term Thoennessen expects the country to maintain its supremacy with the Facility for Rare Isotope Beams (FRIB), construction of which is expected to begin in 2012 at Michigan State University. Not everyone agrees that this ranking is the best way to capture the science of the field. Krzysztof Rykaczewski, a nuclear physicist at Oak Ridge National Laboratory in Tennessee, who according to Thoennessen's list has discovered 60 isotopes, would like to see a ranking include not only discoveries, but also the first person to study the properties and nuclear structure of the atoms. "Identifying is only the first step," he says. But Patrick Regan, a physicist at the University of Surrey in Guildford, UK, who has 20 isotope discoveries to his name, thinks that the discovery itself does reflect something important. "I'm proud of each one of those 20," he says, "each of them is like a child to science." Thoennessen set the bar high when deciding what counted as a discovery, in the hope of improving standards in the field. He considers an isotope "discovered" only if its mass and charge have been identified in a peer-reviewed paper. As he dug into the literature, he found that some generally accepted isotopes in fact appeared only in less rigorously vetted sources, such as PhD theses, conference proceedings or unpublished 'private communications'. He discounted such discoveries. "There are numbers people take for granted where one really shouldn't," says Thoennessen. One person who is pleasantly surprised by the ranking is Münzenberg. He was aware that he had made a large contribution, including discovering elements 107–112 and some of their isotopes, but he hadn't realized that he would be top in the world. "I didn't know how many we'd made," he says. GSI Darmstadt is expected to announce a further 60 isotopes in the next year, and as equipment Münzenberg designed is still in use he may well remain ahead for the foreseeable future.
Valverde A.A.,National Superconducting Cyclotron Laboratory |
Valverde A.A.,Michigan State University |
Bollen G.,Michigan State University |
Brodeur M.,University of Notre Dame |
And 17 more authors.
Physical Review Letters | Year: 2015
We report the first direct measurement of the O14 superallowed Fermi β-decay QEC value, the last of the so-called "traditional nine" superallowed Fermi β decays to be measured with Penning trap mass spectrometry. O14, along with the other low-Z superallowed β emitter, C10, is crucial for setting limits on the existence of possible scalar currents. The new ground state QEC value, 5144.364(25) keV, when combined with the energy of the 0+ daughter state, Ex(0+)=2312.798(11)keV [F. Ajzenberg-Selove, Nucl. Phys. A523, 1 (1991)], provides a new determination of the superallowed β-decay QEC value, QEC(sa)=2831.566(28)keV, with an order of magnitude improvement in precision, and a similar improvement to the calculated statistical rate function f. This is used to calculate an improved Ft value of 3073.8(2.8) s. © 2015 American Physical Society.
PubMed | National Superconducting Cyclotron Laboratory, Facility for Rare Isotope Beams, Michigan State University, Central Michigan University and University of Notre Dame
Type: Journal Article | Journal: Physical review letters | Year: 2016
We report the determination of the Q(EC) value of the mirror transition of (11)C by measuring the atomic masses of (11)C and (11)B using Penning trap mass spectrometry. More than an order of magnitude improvement in precision is achieved as compared to the 2012 Atomic Mass Evaluation (Ame2012) [Chin. Phys. C 36, 1603 (2012)]. This leads to a factor of 3 improvement in the calculated Ft value. Using the new value, Q(EC)=1981.690(61)keV, the uncertainty on Ft is no longer dominated by the uncertainty on the Q(EC) value. Based on this measurement, we provide an updated estimate of the Gamow-Teller to Fermi mixing ratio and standard model values of the correlation coefficients.
News Article | February 18, 2017
Cosmic detonations of this scale and larger created many of the atoms in our bodies, says Michigan State University's Christopher Wrede, who presented at the American Association for the Advancement of Science meeting. A safe way to study these events in laboratories on Earth is to investigate the exotic nuclei or "rare isotopes" that influence them. "Astronomers observe exploding stars and astrophysicists model them on supercomputers," said Wrede, assistant professor of physics at MSU's National Superconducting Cyclotron Laboratory. "At NSCL and, in the future at the Facility for Rare Isotope Beams, we're able to measure the nuclear properties that drive stellar explosions and synthesize the chemical elements - essential input for the models. Rare isotopes are like the DNA of exploding stars." Wrede's presentation explained how rare isotopes are produced and studied at MSU's NSCL, and how they shed light on the evolution of visible matter in the universe. "Rare isotopes will help us to understand how stars processed some of the hydrogen and helium gas from the Big Bang into elements that make up solid planets and life," Wrede said. "Experiments at rare isotope beam facilities are beginning to provide the detailed nuclear physics information needed to understand our origins." In a recent experiment, Wrede's team investigated stellar production of the radioactive isotope aluminum-26 present in the Milky Way. An injection of aluminum-26 into the nebula that formed the solar system could have influenced the amount of water on Earth. Using a rare isotope beam created at NSCL, the team determined the last unknown nuclear-reaction rate affecting the production of aluminum-26 in classical novae. They concluded that up to 30 percent could be produced in novae, and the rest must be produced in other sources like supernovae. Future research can now focus on counting the number of novae in the galaxy per year, modeling the hydrodynamics of novae and investigating the other sources in complete nuclear detail. To extend their reach to more extreme astrophysical events, nuclear scientists are continuing to improve their technology and techniques. Traditionally, stable ion beams have been used to measure nuclear reactions. For example, bombarding a piece of aluminum foil with a beam of protons can produce silicon atoms. However, exploding stars make radioactive isotopes of aluminum that would decay into other elements too quickly to make a foil target out of them. "With FRIB, we will reverse the process; we'll create a beam of radioactive aluminum ions and use it to bombard a target of protons," Wrede said. "Once FRIB comes online, we will be able to measure many more of the nuclear reactions that affect exploding stars." Explore further: Dust grains could be remnants of stellar explosions billions of years ago
News Article | March 30, 2016
Michigan State University researchers, working with colleagues from Technical University Darmstadt in Germany, are zeroing in on the answer to one of science's most puzzling questions: Where did heavy elements, such as gold, originate? Currently there are two candidates, neither of which are located on Earth - a supernova, a massive star that, in its old age, collapsed and then catastrophically exploded under its own weight; or a neutron-star merger, in which two of these small yet incredibly massive stars come together and spew out huge amounts of stellar debris. In a recently published paper in the journal Physical Review Letters, the researchers detail how they are using computer models to come closer to an answer. "At this time, no one knows the answer," said Witold Nazarewicz, a professor at the MSU-based Facility for Rare Isotope Beams and one of the co-authors of the paper. "But this work will help guide future experiments and theoretical developments." By using existing data, often obtained by means of high-performance computing, the researchers were able to simulate production of heavy elements in both supernovae and neutron-star mergers. "Our work shows regions of elements where the models provide a good prediction," said Nazarewicz, a Hannah Distinguished Professor of Physics who also serves as FRIB's chief scientist. "What we can do is identify the critical areas where future experiments, which will be conducted at FRIB, will work to reduce uncertainties of nuclear models." Other researchers included Dirk Martin and Almudena Arcones from Technical University Darmstadt and Erik Olsen of MSU. MSU is establishing FRIB as a new scientific user facility for the Office of Nuclear Physics in the U.S. Department of Energy Office of Science. Explore further: Researchers make precise measurements of the half-lives of previously unmeasured nuclei More information: D. Martin et al. Impact of Nuclear Mass Uncertainties on the Process , Physical Review Letters (2016). DOI: 10.1103/PhysRevLett.116.121101
News Article | February 18, 2017
EAST LANSING, Mich. - Imagine being able to view microscopic aspects of a classical nova, a massive stellar explosion on the surface of a white dwarf star (about as big as Earth), in a laboratory rather than from afar via a telescope. Cosmic detonations of this scale and larger created many of the atoms in our bodies, says Michigan State University's Christopher Wrede, who presented at the American Association for the Advancement of Science meeting. A safe way to study these events in laboratories on Earth is to investigate the exotic nuclei or "rare isotopes" that influence them. "Astronomers observe exploding stars and astrophysicists model them on supercomputers," said Wrede, assistant professor of physics at MSU's National Superconducting Cyclotron Laboratory. "At NSCL and, in the future at the Facility for Rare Isotope Beams, we're able to measure the nuclear properties that drive stellar explosions and synthesize the chemical elements - essential input for the models. Rare isotopes are like the DNA of exploding stars." Wrede's presentation explained how rare isotopes are produced and studied at MSU's NSCL, and how they shed light on the evolution of visible matter in the universe. "Rare isotopes will help us to understand how stars processed some of the hydrogen and helium gas from the Big Bang into elements that make up solid planets and life," Wrede said. "Experiments at rare isotope beam facilities are beginning to provide the detailed nuclear physics information needed to understand our origins." In a recent experiment, Wrede's team investigated stellar production of the radioactive isotope aluminum-26 present in the Milky Way. An injection of aluminum-26 into the nebula that formed the solar system could have influenced the amount of water on Earth. Using a rare isotope beam created at NSCL, the team determined the last unknown nuclear-reaction rate affecting the production of aluminum-26 in classical novae. They concluded that up to 30 percent could be produced in novae, and the rest must be produced in other sources like supernovae. Future research can now focus on counting the number of novae in the galaxy per year, modeling the hydrodynamics of novae and investigating the other sources in complete nuclear detail. To extend their reach to more extreme astrophysical events, nuclear scientists are continuing to improve their technology and techniques. Traditionally, stable ion beams have been used to measure nuclear reactions. For example, bombarding a piece of aluminum foil with a beam of protons can produce silicon atoms. However, exploding stars make radioactive isotopes of aluminum that would decay into other elements too quickly to make a foil target out of them. "With FRIB, we will reverse the process; we'll create a beam of radioactive aluminum ions and use it to bombard a target of protons," Wrede said. "Once FRIB comes online, we will be able to measure many more of the nuclear reactions that affect exploding stars." MSU is establishing FRIB as a new scientific user facility for the Office of Nuclear Physics in the U.S. Department of Energy Office of Science. Under construction on campus and operated by MSU, FRIB will enable scientists to make discoveries about the properties of rare isotopes in order to better understand the physics of nuclei, nuclear astrophysics, fundamental interactions, and applications for society, including in medicine, homeland security and industry. Project completion is expected in 2022, with the project team managing to early completion in fiscal year 2021. Michigan State University has been working to advance the common good in uncommon ways for more than 150 years. One of the top research universities in the world, MSU focuses its vast resources on creating solutions to some of the world's most pressing challenges, while providing life-changing opportunities to a diverse and inclusive academic community through more than 200 programs of study in 17 degree-granting colleges. For MSU news on the Web, go to MSUToday. Follow MSU News on Twitter at twitter.com/MSUnews.
Romanenko A.,Fermi National Accelerator Laboratory |
Grassellino A.,Fermi National Accelerator Laboratory |
Barkov F.,Fermi National Accelerator Laboratory |
Ozelis J.P.,Facility for Rare Isotope Beams
Physical Review Special Topics - Accelerators and Beams | Year: 2013
The near-surface nanostructure of niobium determines the performance of superconducting microwave cavities. Subtle variations in surface nanostructure lead to yet unexplained phenomena such as the dependence of the quality factor of these resonating structures on the magnitude of rf fields - an effect known as the "Q slopes". Understanding and controlling the Q slopes is of great practical importance for particle accelerators. Here we investigate the mild baking effect - 120 C vacuum baking for 48 hours - which strongly affects the Q slopes. We used a hydrofluoric acid rinse alternating with oxidation in water as a tool for stepwise material removal of about 2 nanometers/step from the surface of superconducting niobium cavities. Applying removal cycles on mild baked cavities and measuring the quality factor dependence on the rf fields after one or several such cycles allowed us to explore the distribution of lossy layers within the first several tens of nanometers from the surface. We found that a single HF rinse results in the increase of the cavity quality factor. The low field Q slope was shown to be mostly controlled by the material structure within the first six nanometers from the surface. The medium field Q slope evolution was fitted using linear (â̂B peak surface magnetic field) and quadratic (â̂B2) terms in the surface resistance and it was found that best fits do not require the quadratic term. We found that about 10 nanometers of material removal are required to bring back the high field Q slope and about 20-50 nanometers to restore the onset field to the prebaking value.
Schwarz S.,National Superconducting Cyclotron Laboratory |
Bollen G.,Facility for Rare Isotope Beams |
Ringle R.,National Superconducting Cyclotron Laboratory |
Savory J.,U.S. National Institute of Standards and Technology |
Schury P.,University of Tsukuba
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2016
This paper presents a detailed description of the ion cooler and buncher, installed at the Low Energy Beam and Ion Trap Facility (LEBIT) at the National Superconducting Cyclotron Laboratory (NSCL). NSCL uses gas stopping to provide rare isotopes from projectile fragmentation for its low-energy physics program and to the re-accelerator ReA. The LEBIT ion buncher converts the continuous rare-isotope beam, delivered from the gas stopping cell, into short, low-emittance ion pulses, required for high-precision mass measurements with a 9.4 T Penning trap mass spectrometer. Operation at cryogenic temperatures, a simplified electrode structure and dedicated rugged electronics contribute to the high performance and reliability of the device, which have been essential to the successful LEBIT physics program since 2005. © 2016 Elsevier B.V.
News Article | March 30, 2016
The heavy element found in mines all around the world may not come from earth. An international team of researchers from the University of Michigan and Germany’s Technical University Darmstadt are exploring that elemental compounds like gold and uranium originate from space. Computer models are helping the scientists explore two popular theories, according to phys.org. One concept is that a dying supernova explodes under its own weight yielding these elements, whereas another is that two neutron stars merging together would produce a staggering amount of stellar debris. An article published in the journal Physical Review Letters explained that the scientists used existing data to simulate the production process of these elements in supernova collapses and the fusion of two neutron stars. Witold Nazarewicz, Ph.D., a co-author of the paper and nuclear physicist at Michigan State’s Facility for Rare Isotope Beams told Phys.org, “Our work shows regions of elements where the models provide a good prediction.” However, Nazarewicz added more research needs to be done in order to reduce uncertainties of these nuclear models, because data currently available is based on theoretical developments. Still, these findings could lay the groundwork for future experiments, he continued. The lack of verified proof, though, that one of these universal occurrences creates these valuable metals isn’t stopping Luxembourg from trying to capitalize on a potential gold rush. The country announced in February it started the first government initiative to establish a legal and regulatory framework for asteroid mining. Establish your company as a technology leader! For more than 50 years, the R&D 100 Awards have showcased new products of technological significance. You can join this exclusive community!