Atoms are the basic particles of the chemical elements. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other by the number of protons that are in their atoms. For example, any atom that contains 11 protons is sodium, and any atom that contains 29 protons is copper. Atoms with the same number of protons but a different number of neutrons are called isotopes of the same element.
Aage Niels Bohr was a Danish nuclear physicist who shared the Nobel Prize in Physics in 1975 with Ben Roy Mottelson and James Rainwater "for the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of the structure of the atomic nucleus based on this connection". His father was Niels Bohr.
In atomic physics, the Bohr model or Rutherford–Bohr model of the atom, presented by Niels Bohr and Ernest Rutherford in 1913, consists of a small, dense nucleus surrounded by orbiting electrons. It is analogous to the structure of the Solar System, but with attraction provided by electrostatic force rather than gravity, and with the electron energies quantized.
Ernest Rutherford, 1st Baron Rutherford of Nelson, was a New Zealand physicist who was a pioneering researcher in both atomic and nuclear physics. Rutherford has been described as "the father of nuclear physics", and "the greatest experimentalist since Michael Faraday". In 1908, he was awarded the Nobel Prize in Chemistry "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances." He was the first Oceanian Nobel laureate, and the first to perform the awarded work in Canada.
Henry Gwyn Jeffreys Moseley was an English physicist, whose contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number. This stemmed from his development of Moseley's law in X-ray spectra.
Sir James Chadwick, was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932. In 1941, he wrote the final draft of the MAUD Report, which inspired the U.S. government to begin serious atom bomb research efforts. He was the head of the British team that worked on the Manhattan Project during World War II. He was knighted in Britain in 1945 for his achievements in physics.
Leo James Rainwater was an American physicist who shared the Nobel Prize in Physics in 1975 for his part in determining the asymmetrical shapes of certain atomic nuclei.
In quantum physics and chemistry, quantum numbers are quantities that characterize the possible states of the system. Quantum numbers are closely related to eigenvalues of observables. When the corresponding observable commutes with the Hamiltonian, the quantum number is said to be "good", and acts as a constant of motion in the quantum dynamics.
In quantum physics, the Stern–Gerlach experiment demonstrated that the spatial orientation of angular momentum is quantized. Thus an atomic-scale system was shown to have intrinsically quantum properties. In the original experiment, silver atoms were sent through a spatially-varying magnetic field, which deflected them before they struck a detector screen, such as a glass slide. Particles with non-zero magnetic moment were deflected, owing to the magnetic field gradient, from a straight path. The screen revealed discrete points of accumulation, rather than a continuous distribution, owing to their quantized spin. Historically, this experiment was decisive in convincing physicists of the reality of angular-momentum quantization in all atomic-scale systems.
Daresbury Laboratory is a scientific research laboratory based at Sci-Tech Daresbury campus near Daresbury in Halton, Cheshire, England. The laboratory began operations in 1962 and was officially opened on 16 June 1967 as the Daresbury Nuclear Physics Laboratory (DNPL) by the then Prime Minister of United Kingdom, Harold Wilson. It was the second national laboratory established by the British National Institute for Research in Nuclear Science, following the Rutherford High Energy Laboratory. It is operated by the Science and Technology Facilities Council, part of UK Research and Innovation. As of 2018, it employs around 300 staff, with Paul Vernon appointed as director in November 2020, taking over from Professor Susan Smith who had been director from 2012.
The Science and Technology Facilities Council (STFC) is a United Kingdom government agency that carries out research in science and engineering, and funds UK research in areas including particle physics, nuclear physics, space science and astronomy.
Witold (Witek) Nazarewicz is a Polish-American nuclear physicist, researcher, and educator. He is a John A. Hannah Distinguished Professor in Physics and Chief Scientist at the Facility for Rare Isotope Beams (FRIB) and the Department of Physics and Astronomy at Michigan State University, and a Professor at the University of Warsaw, Faculty of Physics, Institute of Theoretical Physics.
The Wu experiment was a particle and nuclear physics experiment conducted in 1956 by the Chinese American physicist Chien-Shiung Wu in collaboration with the Low Temperature Group of the US National Bureau of Standards. The experiment's purpose was to establish whether or not conservation of parity (P-conservation), which was previously established in the electromagnetic and strong interactions, also applied to weak interactions. If P-conservation were true, a mirrored version of the world (where left is right and right is left) would behave as the mirror image of the current world. If P-conservation were violated, then it would be possible to distinguish between a mirrored version of the world and the mirror image of the current world.
Albert Edward "Ted" Litherland is a nuclear physicist, known for his pioneering work in accelerator mass spectroscopy (AMS).
The discovery of the neutron and its properties was central to the extraordinary developments in atomic physics in the first half of the 20th century. Early in the century, Ernest Rutherford developed a crude model of the atom, based on the gold foil experiment of Hans Geiger and Ernest Marsden. In this model, atoms had their mass and positive electric charge concentrated in a very small nucleus. By 1920, isotopes of chemical elements had been discovered, the atomic masses had been determined to be (approximately) integer multiples of the mass of the hydrogen atom, and the atomic number had been identified as the charge on the nucleus. Throughout the 1920s, the nucleus was viewed as composed of combinations of protons and electrons, the two elementary particles known at the time, but that model presented several experimental and theoretical contradictions.
Jens Dilling is an experimental nuclear physicist and currently the director of institutional strategic planning at Oak Ridge National Laboratory.
David Maurice Brink was an Australian-British nuclear physicist. He is known for the Axel-Brink hypothesis.
Peter John Twin is a British experimental nuclear physicist. He is known for his research into the structure of atomic nuclei, based upon his pioneering work on techniques of gamma ray spectroscopy and, specifically, the Total Energy Suppression Shield Array (TESSA).
Mark Anthony Riley is a British nuclear physicist. He is known for his work in gamma spectroscopy.
Thomas Lauritsen was an American nuclear physicist best known for his abilities at designing and building experimental facilities and instrumentation for experimental nuclear physics; and as the longtime co-author of a periodic compilation of nuclear data. Except for brief periods abroad, his career was entirely at the California Institute of Technology, mostly as a professor of physics. In 1969 he was elected as a member of the National Academy of Sciences and also the American Academy of Arts and Sciences.
