East Lansing, MI, United States
East Lansing, MI, United States

Time filter

Source Type

News Article | October 26, 2016
Site: www.nature.com

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.


Sarriguren P.,CSIC - Institute for the Structure of Matter | Algora A.,University of Valencia | Algora A.,Hungarian Academy of Sciences | Pereira J.,National Superconducting Cyclotron Laboratory | Pereira J.,Joint Institute for Nuclear Astrophysics JINA
Physical Review C - Nuclear Physics | Year: 2014

β-decay properties of neutron-rich Zr and Mo isotopes are investigated within a microscopic theoretical approach based on the proton-neutron quasiparticle random-phase approximation. The underlying mean field is described self-consistently from deformed Skyrme Hartree-Fock calculations with pairing correlations. Residual separable particle-hole and particle-particle forces are also included in the formalism. The structural evolution in these isotopic chains including both even and odd isotopes is analyzed in terms of the equilibrium deformed shapes. Gamow-Teller strength distributions, β-decay half-lives, and β-delayed neutron-emission probabilities are studied, stressing their relevance to describe the path of the nucleosynthesis rapid neutron capture process. © 2014 American Physical Society.


Mount B.J.,Florida State University | Redshaw M.,Florida State University | Redshaw M.,National Superconducting Cyclotron Laboratory | Myers E.G.,Florida State University
Physical Review C - Nuclear Physics | Year: 2010

The atomic masses of Ge74, Se74, Ge76, and Se76 have been determined from cyclotron frequency ratios of pairs of ions simultaneously trapped in a cryogenic Penning trap. Allowing for cancellation of systematic errors in the mass differences between isobars, we determine the Q value for double-electron capture of Se74 to be 1209.240(7) keV, and the Q value for double-electron emission of Ge76 to be 2039.061(7) keV. The new Q2EC value for Se74 precludes a large resonant enhancement for neutrinoless double-electron capture. © 2010 The American Physical Society.


News Article | February 18, 2017
Site: phys.org

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 | February 18, 2017
Site: www.eurekalert.org

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.


If you could hold bits of stardust on your palm, what would you do? For physicists at Michigan State University, investigating the particles is the best thing to do. The MSU research team is currently investigating microscopic dust grains from a meteoritic material found on our planet in hopes of unlocking secrets of our galaxy. The particles are believed to be spewed out by stellar explosions that occurred prior to the birth of the sun. The study, which will focus on whether these stardust particles came from classical nova explosions or not, is performed inside the university's National Superconducting Cyclotron Laboratory (NSCL). A classical nova is a thermonuclear explosion on the surface of a small star that is part of two stars orbiting each other, or what is called a binary star system. The explosion would have spewed out stellar material in the form of dust and gas into the space between stars in the galaxy. Some of the dust and gas would have been essential in the creation of our own solar system. Christopher Wrede, spokesperson for the study and an assistant professor of physics at MSU, noted a cosmic recycling process at work in the phenomenon. When stars die, they eject dust and gas that often get recycled into the next generation of planets and stars, he said. He and his colleagues at the NSCL conducted an experiment wherein they created and studied the exotic radioactive nuclei that have the strongest influence on the production of silicon isotopes in a series of novae. The team found that the pre-solar grains contain strange amounts of isotope silicon-30 - an isotope that is quite rare on Earth. Scientists know that silicon-30 is created in a classical novae, but do not know enough yet about the nuclear reaction rates in the explosion to be certain how much silicon-30 was created. This makes the origins of the pre-solar grains uncertain. Still, the new nuclear path and computer models of the explosion will help researchers identify the grains. Typical ways to study classical novae is by using telescopes and looking at the light, but Wrede said the pre-solar grains allow them to study the phenomena in a novel way. "[I]f you can actually hold a piece of the star in your hand and study it in detail, that opens a whole new window on these types of stellar explosions," Wrede said. The initial findings are featured in the journal Physical Review Letters.


News Article | October 27, 2016
Site: www.eurekalert.org

Research conducted at the National Superconducting Cyclotron Laboratory at Michigan State University has shed new light on the structure of the nucleus, that tiny congregation of protons and neutrons found at the core of every atom Research conducted at the National Superconducting Cyclotron Laboratory at Michigan State University has shed new light on the structure of the nucleus, that tiny congregation of protons and neutrons found at the core of every atom. Headed by a French research group, the work, detailed in the latest edition of the journal Nature Physics, found that the distribution of the protons in a nucleus known as silicon-34 has a bubble-like center, something scientists had suspected for some time, but hadn't been able to prove. "The finding is somewhat unexpected," said Alexandra Gade, chief scientist at MSU's NSCL, where the work took place. "We've confirmed something that has been suspected for about 40 years but hadn't been observed. This result furthers our understanding of how the nucleus is put together." Usually, the protons and neutrons that make up a nucleus are distributed evenly throughout. So the scientists, as well as the scientific world, took notice when this central depletion of protons was discovered. "What made the work so challenging is the silicon-34 nucleus is an unstable, radioactive isotope, which has a lifetime of just under three seconds," said Daniel Bazin, a member of the team and an NSCL researcher. "These nuclei are difficult to make and there are only a few facilities in the world that can produce them and use them in experiments," Gade said. "In North America, the NSCL is the only facility that could have done this experiment." NSCL is funded by the U.S. National Science Foundation Physics Division to operate a national user facility and for conducting research in nuclear science.


Gebremariam B.,National Superconducting Cyclotron Laboratory | Gebremariam B.,Michigan State University | Duguet T.,National Superconducting Cyclotron Laboratory | Duguet T.,Michigan State University | And 3 more authors.
Physical Review C - Nuclear Physics | Year: 2010

A current objective of low-energy nuclear theory is to build nonempirical nuclear energy density functionals (EDFs) from underlying internucleon interactions and many-body perturbation theory (MBPT). The density matrix expansion (DME) of Negele and Vautherin is a convenient method to map highly nonlocal Hartree-Fock expressions into the form of a quasi-local Skyrme functional with density-dependent couplings. In this work, we assess the accuracy of the DME at reproducing the nonlocal exchange (Fock) contribution to the energy. In contrast to the scalar part of the density matrix for which the original formulation of Negele and Vautherin is reasonably accurate, we demonstrate the necessity to reformulate the DME for the vector part of the density matrix, which is needed for an accurate description of spin-unsaturated nuclei. Phase-space-averaging techniques are shown to yield a significant improvement for the vector part of the density matrix compared to the original formulation of Negele and Vautherin. The key to the improved accuracy is to take into account the anisotropy that characterizes the local momentum distribution in the surface region of finite Fermi systems. Optimizing separately the DME for the central, tensor, and spin-orbit contributions to the Fock energy, one reaches a few-percent accuracy over a representative set of semi-magic nuclei. With such an accuracy at hand, one can envision using the corresponding Skyrme-like energy functional as a microscopically constrained starting point around which future phenomenological parametrizations can be built and refined. © 2010 The American Physical Society.


Ringle R.,National Superconducting Cyclotron Laboratory | Schwarz S.,National Superconducting Cyclotron Laboratory | Bollen G.,National Superconducting Cyclotron Laboratory | Bollen G.,Michigan State University
International Journal of Mass Spectrometry | Year: 2013

The low-energy beam and ion trap facility, LEBIT, has been used to perform high-precision Penning trap mass spectrometry using rare isotopes produced by fast-beam fragmentation. Gas stopping of the fast-fragment beams and advanced ion manipulation techniques are used to produce brilliant, low-energy beams for this type of measurement. The unique combination of fast, high-precision mass spectrometry with the reach beyond the valley of beta stability afforded by projectile fragmentation has made measurements possible that could not be performed at other facilities. © 2013 Elsevier B.V. All rights reserved.


Thoennessen M.,National Superconducting Cyclotron Laboratory
Nuclear Physics A | Year: 2010

The Facility for Rare Isotope Beams (FRIB) will be a new National User Facility for nuclear science, funded by the Department of Energy (DOE), Office of Nuclear Physics (NP) and operated by Michigan State University (MSU). FRIB will cost approximately $550 million to establish and take about a decade to design and build. © 2010 Elsevier B.V. All rights reserved.

Loading National Superconducting Cyclotron Laboratory collaborators
Loading National Superconducting Cyclotron Laboratory collaborators