Can neutrons be absorbed?

Neutrons can indeed be absorbed through a process known as neutron absorption, which involves the capture of a neutron by an atomic nucleus. When a neutron is absorbed by a nucleus, it may result in the formation of a new, heavier isotope of that element or even a different element altogether.

The ability of a nucleus to absorb neutrons is influenced by its atomic structure and the specific isotope involved. Neutron absorption plays a crucial role in various scientific fields, such as nuclear physics and materials science, and has important implications in nuclear reactors and nuclear weapons.

Understanding Neutrons

Neutrons are subatomic particles that make up the nucleus of an atom alongside protons. Unlike protons, neutrons do not carry an electric charge, making them electrically neutral. Due to their lack of charge, neutrons can interact with other particles in unique ways.

Neutron Absorption

Neutron absorption refers to the process in which neutrons are captured by atomic nuclei. This absorption can occur in various materials, including gases, liquids, and solids. However, the extent to which neutrons can be absorbed depends on a few factors.

Nuclear Cross Section

The probability of neutron absorption is measured by the nuclear cross section, which quantifies the likelihood of an atomic nucleus interacting with a neutron. Each atomic nucleus has its own unique cross section value, which can vary depending on the energy of the incoming neutron.

Capturing Neutrons

When a nucleus absorbs a neutron, it can lead to various outcomes. One possibility is the creation of a heavier isotope of the same element. For example, uranium-235 can absorb a neutron and become uranium-236.

Another outcome could involve the emission of particles or gamma rays from the nucleus. These emitted particles can be used in various applications, such as nuclear reactors or radiation therapy.

Neutron Absorption in Different Materials


Some gases, such as helium and neon, have very low probabilities of neutron absorption. This makes them ideal for use as cooling agents or in neutron detectors, as they do not interfere with the neutrons being measured.

On the other hand, some gases, like hydrogen and nitrogen, have higher probabilities of neutron absorption. This characteristic makes them useful for shielding applications, where their high absorption rates can help reduce the intensity of neutron radiation.


Liquids can also exhibit different levels of neutron absorption. Lighter liquids, such as water, have relatively low absorption probabilities. This property makes water a suitable substance for neutron moderation in nuclear reactors, as it can slow down fast neutrons.

Other liquids, like heavy water (deuterium oxide), have higher absorption probabilities. Heavy water is commonly used in nuclear reactors to slow down neutrons and enhance the fission process.


Neutron absorption in solids is highly dependent on the specific material. Some materials, like graphite and beryllium, have low absorption probabilities. This property makes them useful as neutron moderators or reflectors in nuclear reactors.

Other materials, such as cadmium and boron, have high absorption probabilities. These materials are often used as neutron absorbers or control rods in nuclear reactors to regulate the fission process.

Applications of Neutron Absorption

The phenomenon of neutron absorption has various important applications. Here are a few examples:

Nuclear Reactors

In nuclear reactors, neutron absorption plays a crucial role in controlling the rate of fission reactions. Materials with high absorption probabilities, like boron or cadmium, can be inserted or removed from the reactor core to adjust the number of neutrons available for fission. This allows for precise control of the reactor’s power output.

Neutron Imaging

Neutron imaging is a non-destructive imaging technique that utilizes the unique interaction of neutrons with matter. By using materials with different absorption properties, neutron imaging can provide detailed internal images of various objects, such as biological samples, industrial components, and archaeological artifacts.


In the field of medicine, neutron absorption is employed in cancer treatment through a technique known as neutron capture therapy. This therapy uses substances with high neutron absorption probabilities, such as boron compounds, to selectively deliver radiation to cancerous cells while minimizing damage to healthy tissues.

Neutron absorption is a fascinating phenomenon that occurs when neutrons interact with atomic nuclei. The extent to which neutrons can be absorbed depends on factors such as the nuclear cross section and the properties of the material. Understanding neutron absorption is crucial in various fields, including nuclear power generation, imaging, and medicine.

Neutrons can be absorbed through various processes depending on the material they interact with. This property of neutrons plays a crucial role in nuclear reactions, shielding design, and other scientific applications. Understanding neutron absorption is fundamental in advancing research and technology in various fields.

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