Fermium is a synthetic element with the symbol Fm and atomic number 100. It is an actinide and the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not yet been prepared. A total of 19 isotopes are known, with 257Fm being the longest-lived with a half-life of 100.5 days.
The National Superconducting Cyclotron Laboratory (NSCL), located on the campus of Michigan State University was a rare isotope research facility in the United States. Established in 1963, the cyclotron laboratory has been succeeded by the Facility for Rare Isotope Beams, a linear accelerator providing beam to the same detector halls.
Although there are nine known isotopes of helium (2He), only helium-3 and helium-4 are stable. All radioisotopes are short-lived, the longest-lived being 6
He
with a half-life of 806.92(24) milliseconds. The least stable is 10
He
, with a half-life of 260(40) yoctoseconds, although it is possible that 2
He
may have an even shorter half-life.
Flerovium (114Fl) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 289Fl in 1999. Flerovium has seven known isotopes, and possibly 2 nuclear isomers. The longest-lived isotope is 289Fl with a half-life of 1.9 seconds, but the unconfirmed 290Fl may have a longer half-life of 19 seconds.
Calcium-48 is a scarce isotope of calcium containing 20 protons and 28 neutrons. It makes up 0.187% of natural calcium by mole fraction. Although it is unusually neutron-rich for such a light nucleus, its beta decay is extremely hindered, and so the only radioactive decay pathway that it has been observed to undergo is the extremely rare process of double beta decay. Its half-life is about 6.4×1019 years, so for all practical purposes it can be treated as stable. One factor contributing to this unusual stability is that 20 and 28 are both magic numbers, making 48Ca a "doubly magic" nucleus.
The rp-process consists of consecutive proton captures onto seed nuclei to produce heavier elements. It is a nucleosynthesis process and, along with the s-process and the r-process, may be responsible for the generation of many of the heavy elements present in the universe. However, it is notably different from the other processes mentioned in that it occurs on the proton-rich side of stability as opposed to on the neutron-rich side of stability. The end point of the rp-process is not yet well established, but recent research has indicated that in neutron stars it cannot progress beyond tellurium. The rp-process is inhibited by alpha decay, which puts an upper limit on the end point at 104Te, the lightest observed alpha-decaying nuclide, and the proton drip line in light antimony isotopes. At this point, further proton captures result in prompt proton emission or alpha emission, and thus the proton flux is consumed without yielding heavier elements; this end process is known as the tin–antimony–tellurium cycle.
Nuclear astrophysics is an interdisciplinary part of both nuclear physics and astrophysics, involving close collaboration among researchers in various subfields of each of these fields. This includes, notably, nuclear reactions and their rates as they occur in cosmic environments, and modeling of astrophysical objects where these nuclear reactions may occur, but also considerations of cosmic evolution of isotopic and elemental composition (often called chemical evolution). Constraints from observations involve multiple messengers, all across the electromagnetic spectrum (nuclear gamma-rays, X-rays, optical, and radio/sub-mm astronomy), as well as isotopic measurements of solar-system materials such as meteorites and their stardust inclusions, cosmic rays, material deposits on Earth and Moon). Nuclear physics experiments address stability (i.e., lifetimes and masses) for atomic nuclei well beyond the regime of stable nuclides into the realm of radioactive/unstable nuclei, almost to the limits of bound nuclei (the drip lines), and under high density (up to neutron star matter) and high temperature (plasma temperatures up to 109 K). Theories and simulations are essential parts herein, as cosmic nuclear reaction environments cannot be realized, but at best partially approximated by experiments. In general terms, nuclear astrophysics aims to understand the origin of the chemical elements and isotopes, and the role of nuclear energy generation, in cosmic sources such as stars, supernovae, novae, and violent binary-star interactions.
The Joint Institute for Nuclear Astrophysics Center for the Evolution of the Elements (JINA-CEE) is a multi-institutional Physics Frontiers Center funded by the US National Science Foundation since 2014. From 2003 to 2014, JINA was a collaboration between Michigan State University, the University of Notre Dame, the University of Chicago, and directed by Michael Wiescher from the University of Notre Dame. Principal investigators were Hendrik Schatz, Timothy Beers and Jim Truran.
Alastair G. W. Cameron was an American-Canadian astrophysicist and space scientist who was an eminent staff member of the Astronomy department of Harvard University. He was one of the founders of the field of nuclear astrophysics, advanced the theory that the Moon was created by the giant impact of a Mars-sized object with the early Earth, and was an early adopter of computer technology in astrophysics.
Carlos A. Bertulani is a Brazilian and American theoretical physicist and professor at the department of physics of the Texas A&M University-Commerce. He graduated, PhD, at University of Bonn and works on nuclear physics and nuclear astrophysics. He was formerly a professor at the Federal University of Rio de Janeiro from 1980-2000.
John Myrick Dawson was an American computational physicist and the father of plasma-based acceleration techniques. Dawson earned his degrees in physics from the University of Maryland, College Park: a B.S. in 1952 and Ph.D. in 1957. His thesis "Distortion of Atoms and Molecules in Dense Media" was prepared under the guidance of Zaka Slawsky.
The nuclear drip line is the boundary beyond which atomic nuclei are unbound with respect to the emission of a proton or neutron.
p-nuclei (p stands for proton-rich) are certain proton-rich, naturally occurring isotopes of some elements between selenium and mercury inclusive which cannot be produced in either the s- or the r-process.
Artemisia (Artemis) Spyrou is an experimental nuclear astrophysicist and professor at Michigan State University. She is also the Associate Director for Education and Outreach at the National Superconducting Cyclotron Laboratory. She was the recipient of a NSF CAREER Award.
Ani Aprahamian is a Lebanese-born Armenian-American nuclear physicist. She has taught at the University of Notre Dame since 1989. She is currently Freimann Professor of Physics at Notre Dame. She has been director of the Alikhanyan National Science Laboratory in Armenia since April 2018, the first woman to hold the position.
Kevin Insik Hahn is a South Korean physicist who is an expert in the fields of nuclear physics and nuclear astrophysics. Since December 2019, he has been the director of the Center for Exotic Nuclear Studies at the Institute for Basic Science (IBS) in South Korea. He also holds an endowed professorship in the Department of Science Education at Ewha Womans University, where he has worked since 1999. In his research, he has worked on accelerator-based as well as non-accelerator-based experiments. His current research activities involve a number of accelerators around the world, including the RI Beam Factory (RIBF) at RIKEN, Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, and the soon-to-open Rare isotope Accelerator complex for ON-line experiment (RAON). During his tenure at Ewha Womans University, he promoted STEM/STEAM education by serving for multiple years as the director of the Advanced STEAM Teacher Education Center. He also wrote several physics textbooks for high school students and undergraduate students.
Christopher John Pethick is a British theoretical physicist, specializing in many-body theory, ultra-cold atomic gases, and the physics of neutron stars and stellar collapse.
Eric B. Norman is an American physicist. He is a professor in the graduate school of the University of California, Berkeley.
Michael C. F. Wiescher is a German-American experimental nuclear physicist and astrophysicist, known for his laboratory research in nuclear physics connected with various astrophysical phenomena such as stellar evolution and explosion environments.
Daniel S. Akerib is an American particle physicist and astrophysicist. He was elected in 2008 a fellow of the American Physical Society (APS).
