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237 Np is the product of alpha decay of 241 Am, which is produced through neutron irradiation of uranium-238. [28] Heavier isotopes of neptunium decay quickly, and lighter isotopes of neptunium cannot be produced by neutron capture, so chemical separation of neptunium from cooled spent nuclear fuel gives nearly pure 237 Np. [28]
Neutron radiation is a form of ionizing radiation that presents as free neutrons.Typical phenomena are nuclear fission or nuclear fusion causing the release of free neutrons, which then react with nuclei of other atoms to form new nuclides—which, in turn, may trigger further neutron radiation.
is the only neptunium isotope produced in significant quantity in the nuclear fuel cycle, both by successive neutron capture by uranium-235 (which fissions most but not all of the time) and uranium-236, or (n,2n) reactions where a fast neutron occasionally knocks a neutron loose from uranium-238 or isotopes of plutonium. Over the long term, 237 Np
Even neutrons without significant kinetic energy are indirectly ionizing, and are thus a significant radiation hazard. Not all materials are capable of neutron activation; in water, for example, the most common isotopes of both types atoms present (hydrogen and oxygen) capture neutrons and become heavier but remain stable forms of those atoms.
The actinide series is a group of chemical elements with atomic numbers ranging from 89 to 102, [note 1] including notable elements such as uranium and plutonium.The nuclides (or isotopes) thorium-232, uranium-235, and uranium-238 occur primordially, while trace quantities of actinium, protactinium, neptunium, and plutonium exist as a result of radioactive decay and (in the case of neptunium ...
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 ...
On May 27, Edwin McMillan and Philip Abelson publish the discovery of neptunium at the Berkeley Radiation Laboratory. They use the 60-inch cyclotron produce a small sample of neptunium-239 via neutron bombardment of uranium-238. They also correctly assume its beta decay to the alpha-emitting plutonium-239, but are unable to isolate it. [23]
The radionuclide used is americium-241, which is created by bombarding plutonium with neutrons in a nuclear reactor. It decays by emitting alpha particles and gamma radiation to become neptunium-237. Smoke detectors use a very small quantity of 241 Am (about 0.29 micrograms per smoke detector) in the form of americium dioxide.