The neutron is a subatomic particle, symbol
n
or
n0
, that has no electric charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behave similarly within the nucleus, they are both referred to as nucleons. Nucleons have a mass of approximately one atomic mass unit, or dalton. Their properties and interactions are described by nuclear physics. Protons and neutrons are not elementary particles; each is composed of three quarks.
A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. When a fissile nucleus like uranium-235 or plutonium-239 absorbs a neutron, it splits into lighter nuclei, releasing energy, gamma radiation, and free neutrons, which can induce further fission in a self-sustaining chain reaction. The process is carefully controlled using control rods and neutron moderators to regulate the number of neutrons that continue the reaction, ensuring the reactor operates safely, although inherent control by means of delayed neutrons also plays an important role in reactor output control. The efficiency of nuclear fuel is much higher than fossil fuels; the 5% enriched uranium used in the newest reactors has an energy density 120,000 times higher than coal.
Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by nuclear fission of uranium and plutonium in nuclear power plants. Nuclear decay processes are used in niche applications such as radioisotope thermoelectric generators in some space probes such as Voyager 2. Reactors producing controlled fusion power have been operated since 1958 but have yet to generate net power and are not expected to be commercially available in the near future.
Theodore Brewster "Ted" Taylor was an American theoretical physicist, specifically concerning nuclear energy. His higher education included a PhD from Cornell University in theoretical physics. His most noteworthy contributions to the field of nuclear weaponry were his small bomb developments at the Los Alamos Laboratory in New Mexico. Although not widely known to the general public, Taylor is credited with numerous landmarks in fission nuclear weaponry development, including having designed and developed the smallest, most powerful, and most efficient fission weapons ever tested by the US. Though not considered a brilliant physicist from a calculative viewpoint, his vision and creativity allowed him to thrive in the field. The later part of Taylor's career was focused on nuclear energy instead of weaponry, and included his work on Project Orion, nuclear reactor developments, and anti-nuclear proliferation.
Nuclear technology is technology that involves the nuclear reactions of atomic nuclei. Among the notable nuclear technologies are nuclear reactors, nuclear medicine and nuclear weapons. It is also used, among other things, in smoke detectors and gun sights.
Frederick Reines was an American physicist. He was awarded the 1995 Nobel Prize in Physics for his co-detection of the neutrino with Clyde Cowan in the neutrino experiment. He may be the only scientist in history "so intimately associated with the discovery of an elementary particle and the subsequent thorough investigation of its fundamental properties."
Nuclear Weapons Design are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types:
A neutron source is any device that emits neutrons, irrespective of the mechanism used to produce the neutrons. Neutron sources are used in physics, engineering, medicine, nuclear weapons, petroleum exploration, biology, chemistry, and nuclear power. Neutron source variables include the energy of the neutrons emitted by the source, the rate of neutrons emitted by the source, the size of the source, the cost of owning and maintaining the source, and government regulations related to the source.
Luis Walter Alvarez was an American experimental physicist, inventor, and professor who was awarded the Nobel Prize in Physics in 1968 for his discovery of resonance states in particle physics using the hydrogen bubble chamber. In 2007 the American Journal of Physics commented, "Luis Alvarez was one of the most brilliant and productive experimental physicists of the twentieth century."
Radiological warfare is any form of warfare involving deliberate radiation poisoning or contamination of an area with radiological sources.
Nuclear propulsion includes a wide variety of propulsion methods that use some form of nuclear reaction as their primary power source. The idea of using nuclear material for propulsion dates back to the beginning of the 20th century. In 1903 it was hypothesized that radioactive material, radium, might be a suitable fuel for engines to propel cars, planes, and boats. H. G. Wells picked up this idea in his 1914 fiction work The World Set Free. Many aircraft carriers and submarines currently use uranium fueled nuclear reactors that can provide propulsion for long periods without refueling. There are also applications in the space sector with nuclear thermal and nuclear electric engines which could be more efficient than conventional rocket engines.
David Charles Hahn, sometimes called the "Radioactive Boy Scout" and the "Nuclear Boy Scout" was an American nuclear radiation enthusiast who built a homemade neutron source at the age of seventeen.
Neutron activation is the process in which neutron radiation induces radioactivity in materials, and occurs when atomic nuclei capture free neutrons, becoming heavier and entering excited states. The excited nucleus decays immediately by emitting gamma rays, or particles such as beta particles, alpha particles, fission products, and neutrons. Thus, the process of neutron capture, even after any intermediate decay, often results in the formation of an unstable activation product. Such radioactive nuclei can exhibit half-lives ranging from small fractions of a second to many years.
A thermonuclear weapon, fusion weapon or hydrogen bomb (H bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lower mass, or a combination of these benefits. Characteristics of nuclear fusion reactions make possible the use of non-fissile depleted uranium as the weapon's main fuel, thus allowing more efficient use of scarce fissile material such as uranium-235 or plutonium-239. The first full-scale thermonuclear test was carried out by the United States in 1952, and the concept has since been employed by most of the world's nuclear powers in the design of their weapons.
Monte Carlo N-Particle Transport (MCNP) is a general-purpose, continuous-energy, generalized-geometry, time-dependent, Monte Carlo radiation transport code designed to track many particle types over broad ranges of energies and is developed by Los Alamos National Laboratory. Specific areas of application include, but are not limited to, radiation protection and dosimetry, radiation shielding, radiography, medical physics, nuclear criticality safety, detector design and analysis, nuclear oil well logging, accelerator target design, fission and fusion reactor design, decontamination and decommissioning. The code treats an arbitrary three-dimensional configuration of materials in geometric cells bounded by first- and second-degree surfaces and fourth-degree elliptical tori.
Applied physics is the application of physics to solve scientific or engineering problems. It is usually considered a bridge or a connection between physics and engineering. "Applied" is distinguished from "pure" by a subtle combination of factors, such as the motivation and attitude of researchers and the nature of the relationship to the technology or science that may be affected by the work. Applied physics is rooted in the fundamental truths and basic concepts of the physical sciences but is concerned with the utilization of scientific principles in practical devices and systems and with the application of physics in other areas of science and high technology.
Thiago David Olson is a venture capitalist, electrical engineer and entrepreneur. Olson is the co-founder and CEO of Stratos Technologies, Inc., creators of the Stratos Card. As an electrical engineer Olson became known as a teenager for his research in Nuclear Fusion and Neutron Sciences. As a 17-year-old, attending Stoney Creek High School in Rochester Hills, Michigan, Olson created a homemade nuclear fusion reactor. In his article Neutron activation analysis using an inertial electrostatic confinement fusion device he indicated that his apparatus did not produce surplus energy.
Robert W. Conn was president and chief executive officer of The Kavli Foundation from 2009 to 2020, a U.S. based foundation dedicated to the advancement of basic science research and public interest in science. A physicist and engineer, Conn was also the board chair of the Science Philanthropy Alliance, an organization that aims to increase private support for basic science research, and dean emeritus of the Jacobs School of Engineering at the University of California, San Diego. In the 1970s and 1980s, Conn participated in some of the earliest studies of fusion energy as a potential source of electricity, and he served on numerous federal panels, committees, and boards advising the government on the subject. In the early 1970s, he co-founded the Fusion Technology Institute at the University of Wisconsin-Madison (UW), and in the mid-1980s he led the formation of the Institute of Plasma and Fusion Research at the University of California, Los Angeles (UCLA). As a university administrator in the 1990s and early 2000s, Conn served as dean of the school of engineering at UC San Diego as it established several engineering institutes and programs, including the California Institute for Telecommunications and Information Technology, known as Calit2, the Center for Wireless Communications, and the Whitaker Center for Biomedical Engineering. While at UC San Diego he also led the effort to establish an endowment for the school of engineering, which began with major gifts from Irwin and Joan Jacobs. Irwin M. Jacobs is the co-founder and founding CEO of Qualcomm. While Conn was dean, the engineering school was renamed in 1998 the Irwin and Joan Jacobs School of Engineering at UC San Diego. Conn's experience in the private sector includes co-founding in 1986 Plasma & Materials Technologies, Inc. (PMT), and serving as managing director of Enterprise Partners Venture Capital (EPVC) from 2002 to 2008. Over the years he has served on numerous private and public company corporate boards. Conn joined The Kavli Foundation in 2009. He helped establish the Science Philanthropy Alliance in 2012.
Shyam Sunder Kapoor is an Indian nuclear physicist and a former director of Bhabha Atomic Research Centre. Known for his research on fission and heavy-ion physics, Kapoor is an elected fellow of all the three major Indian science academies – Indian Academy of Sciences, Indian National Science Academy and National Academy of Sciences, India – as well as the Institute of Physics. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards, for his contributions to Physical Sciences in 1983.
