What is neutrino radiation

Neutron radiation

Neutron radiation is ionizing radiation, the components of which are neutrons.

Since neutrons are electrically neutral, neutron radiation has a high penetrating power in matter, similar to gamma radiation. The ionizing effect arises indirectly, mostly through the impact of light atomic nuclei or their components (e.g. protons), which in turn have an ionizing effect.

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Cosmic radiation releases natural neutron radiation in the atmosphere or on the ground through interaction with molecules. Neutron radiation is seldom produced by the natural decay of atomic nuclei; they are produced artificially with the help of neutron sources. In the nuclear reactor, during nuclear fission, neutrons are released.

Another powerful source are neutron bombs. They are supposed to kill people in the target area with the help of neutron radiation, but leave the building and infrastructure relatively undamaged so that they can be used again.

use

In materials research, neutron beams are used to determine the atomic or molecular structure of solids (neutron scattering). To monitor the sub-criticality of a nuclear reactor, the neutron radiation can e.g. B. a radium-beryllium neutron source can be used. In radiation therapy for malignant tumors, attempts were made to kill cancer cells with neutron beams - however, severe side effects quickly became apparent in healthy tissue, which led to a move away from the use of neutrons in radiation oncology.

Harmful effect

The most important harmful effect more quickly Neutrons in living tissue is the elastic scattering of hydrogen. It generates recoil protons, which in turn have a strong ionizing effect and thus have a damaging effect on the tissue.

Indirect damage caused by thermal Neutron radiation comes about through the gamma radiation that is created when the neutron is captured by hydrogen.

The harmfulness of neutron radiation is also shown by the high radiation weighting factors $ \ mathrm {w_R} $ of the German Radiation Protection Ordinance with values ​​from 5 to 20.

In addition, both fast and thermal neutron radiation can convert stable atomic nuclei through nuclear reactions into radioactive atomic nuclei - the so-called activation.

shielding

The shielding of neutron radiation usually takes place with several processes (see also shielding (radiation)): A moderator, for example water, paraffin or PVC, slows down fast free neutrons and converts part of the kinetic energy into heat. The then thermal neutrons are adsorbed by, for example, cadmium or boron. The accompanying gamma radiation can finally be reduced by a layer of lead.

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