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Neutron activation
 
 
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Neutron activation is the process in which neutron radiation
Neutron radiation

Neutron radiation is a kind of non-ionizing radiation which consists of free neutrons....
 induces radioactivity in materials, and occurs when atomic nuclei
Atomic nucleus

The nucleus of an atom is the very dense region, consisting of nucleons , at the center of an atom. Although the size of the nucleus varies considerably according to the mass of the atom, the size of the entire atom is comparatively constant....
 capture free neutrons, becoming heavier and entering excited state
Excited state

Excitation is an elevation in energy level above an arbitrary baseline energy state. In physics there is a specific technical definition for energy level which is often associated with an atom being excited to an excited state....
s. The excited nucleus often decays immediately by emitting particles such as neutrons, proton
Proton

The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+....
s, or alpha particle
Alpha particle

Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium atomic nucleus; hence, it can be written as He2+ or 42He2+....
s. The neutron capture
Neutron capture

Neutron capture is a kind of nuclear reaction in which an atomic nucleus collides with one or more neutrons and they merge to form a heavier nucleus....
, even after any immediate decay, often results in the formation of an unstable activation product
Activation product

Activation products are materials made radioactive by neutron activation.Fission products and actinides produced by neutron absorption of nuclear fuel itself are normally referred to by those specific names, and activation product reserved for products of neutron capture by other materials, such as structural components of the nuclear r...
. Such radioactive nuclei can exhibit half-lives
Half-life

The half-life of a quantity whose value decreases with time is the interval required for the quantity to decay to half of its initial value. The concept originated in describing how long it takes atoms to undergo radioactive decay but also applies in a wide variety of other situations....
 ranging from fractions of a second to many years.

In places with high neutron flux
Neutron flux

Neutron flux is a term referring to the number of neutrons passing through an area over a span of time. It is most commonly measured in neutrons/....
es, such as nuclear reactor
Nuclear reactor

A nuclear reactor is a device in which nuclear chain reactions are initiated, controlled, and sustained at a steady rate, as opposed to a nuclear bomb, in which the chain reaction occurs in a fraction of a second and is uncontrolled causing an explosion....
 cores, neutron activation contributes to material erosion, and the materials themselves must be disposed of as low-level radioactive waste
Radioactive waste

Radioactive wastes are waste types containing radioactive decay chemical elements that do not have a practical purpose. They are usually the products of nuclear processes, such as nuclear fission....
.






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Neutron activation is the process in which neutron radiation
Neutron radiation

Neutron radiation is a kind of non-ionizing radiation which consists of free neutrons....
 induces radioactivity in materials, and occurs when atomic nuclei
Atomic nucleus

The nucleus of an atom is the very dense region, consisting of nucleons , at the center of an atom. Although the size of the nucleus varies considerably according to the mass of the atom, the size of the entire atom is comparatively constant....
 capture free neutrons, becoming heavier and entering excited state
Excited state

Excitation is an elevation in energy level above an arbitrary baseline energy state. In physics there is a specific technical definition for energy level which is often associated with an atom being excited to an excited state....
s. The excited nucleus often decays immediately by emitting particles such as neutrons, proton
Proton

The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+....
s, or alpha particle
Alpha particle

Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium atomic nucleus; hence, it can be written as He2+ or 42He2+....
s. The neutron capture
Neutron capture

Neutron capture is a kind of nuclear reaction in which an atomic nucleus collides with one or more neutrons and they merge to form a heavier nucleus....
, even after any immediate decay, often results in the formation of an unstable activation product
Activation product

Activation products are materials made radioactive by neutron activation.Fission products and actinides produced by neutron absorption of nuclear fuel itself are normally referred to by those specific names, and activation product reserved for products of neutron capture by other materials, such as structural components of the nuclear r...
. Such radioactive nuclei can exhibit half-lives
Half-life

The half-life of a quantity whose value decreases with time is the interval required for the quantity to decay to half of its initial value. The concept originated in describing how long it takes atoms to undergo radioactive decay but also applies in a wide variety of other situations....
 ranging from fractions of a second to many years.

In places with high neutron flux
Neutron flux

Neutron flux is a term referring to the number of neutrons passing through an area over a span of time. It is most commonly measured in neutrons/....
es, such as nuclear reactor
Nuclear reactor

A nuclear reactor is a device in which nuclear chain reactions are initiated, controlled, and sustained at a steady rate, as opposed to a nuclear bomb, in which the chain reaction occurs in a fraction of a second and is uncontrolled causing an explosion....
 cores, neutron activation contributes to material erosion, and the materials themselves must be disposed of as low-level radioactive waste
Radioactive waste

Radioactive wastes are waste types containing radioactive decay chemical elements that do not have a practical purpose. They are usually the products of nuclear processes, such as nuclear fission....
. Some materials are more subject to neutron activation than others, so a suitably chosen low-activation material can significantly reduce these problems. One way to demonstrate that nuclear fusion
Nuclear fusion

In nuclear physics and nuclear chemistry, nuclear fusion is the process by which multiple like-charged atomic nuclei join together to form a heavier nucleus....
 is occurring inside a Farnsworth-Hirsch fusor is to use a Geiger counter
Geiger counter

A Geiger counter, also called a Geiger-M?ller counter, is a type of particle detector that measures ionizing radiation....
 to measure the radioactivity induced in a sheet of aluminum foil.

The lasting radiation from a nuclear weapon
Nuclear weapon

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either nuclear fission or a combination of fission and nuclear fusion....
 is in large part due to the neutron activation of the bomb itself and the surrounding material.

Neutron activation also has a practical use. Neutron activation analysis
Neutron activation analysis

Neutron Activation Analysis is a nuclear reaction process used for determining certain concentrations of chemical element in a vast amount of materials....
 is one of the most sensitive and accurate methods of trace element analysis. It requires no sample preparation or solubilization and can therefore be applied to objects that need to be kept intact such as a valuable piece of art. Although the activation induces radioactivity in the object, its level is typically low and its lifetime may be short, so that its effects soon disappear. In this sense, neutron activation is a non-destructive analysis method.

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