A californium neutron flux multiplier (CFX) is a source of

neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...

s for research purposes. It contains a small amount of

californium-252 Californium (98Cf) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 245Cf in 1950. There are 20 known radioisotopes rang ...

and several plates of

highly enriched uranium Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238U ...

(

uranium-235 Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exis ...

) in a

subcritical In nuclear engineering, a critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties (specifically, its nuclear fissio ...

configuration. As the californium undergoes spontaneous

nuclear decay Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consid ...

, it emits neutrons, which bombard the uranium and cause it to decay as well, emitting still more neutrons. This induced fission cascade generates a beam of neutrons that can be used for a variety of imaging and analytical techniques. Rather than relying solely on a large amount of californium for neutrons, the multiplier effect of 3.5 pounds of uranium initiated by only a few milligrams of ²⁵²Cf provided a higher ultimate

neutron flux The neutron flux, φ, is a scalar quantity used in nuclear physics and nuclear reactor physics. It is the total length travelled by all free neutrons per unit time and volume. Equivalently, it can be defined as the number of neutrons travelling ...

at a lower cost. The CFX was designed by IRT Corporation, with two devices manufactured. The first was installed at the

Eastman Kodak The Eastman Kodak Company (referred to simply as Kodak ) is an American public company that produces various products related to its historic basis in analogue photography. The company is headquartered in Rochester, New York, and is incorpor ...

facility in

Rochester, New York Rochester () is a City (New York), city in the U.S. state of New York (state), New York, the county seat, seat of Monroe County, New York, Monroe County, and the fourth-most populous in the state after New York City, Buffalo, New York, Buffalo, ...

in 1975 and decommissioned in 2006–2007. The second was installed at the

US Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United State ...

Mound Laboratories Mound Laboratory in Miamisburg, Ohio was an Atomic Energy Commission (later Department of Energy) facility for nuclear weapon research during the Cold War, named after the nearby Miamisburg Indian Mound. The laboratory grew out of the World War ...

in Ohio, eventually being decommissioned in the 1990s. Kodak used their device for

neutron activation analysis Neutron activation analysis (NAA) is the nuclear process used for determining the concentrations of elements in many materials. NAA allows discrete sampling of elements as it disregards the chemical form of a sample, and focuses solely on atomic ...

and

neutron radiography Neutron imaging is the process of making an image with neutrons. The resulting image is based on the neutron attenuation properties of the imaged object. The resulting images have much in common with industrial X-ray images, but since the image i ...

References

* * Neutron sources Neutron flux multiplier Uranium {{nuclear-tech-stub