EMF behaves like a photon

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Radiation transports energy - starting from a radiation source. The energy is transported in the form of electromagnetic waves (such as with X-rays) or as a particle stream (for example with alpha or beta radiation).

With ionizing radiation there is a greater energy transport (per photon) than with visible light or infrared radiation (thermal radiation). This can change matter into which ionizing radiation penetrates. Chemical bonds can be broken or atoms and molecules can be ionized. Ionization means: electrons are "knocked out" of the shell of atoms or molecules. The remaining atom or molecule is then (at least for a short time) electrically positively charged. Electrically charged particles are called ions.

When ionizing radiation hits living cells or organisms, it can cause damage in the cells and organisms through these ionization processes or through other changes in molecules.

Ionizing radiation and radioactivity

Ionizing radiation can be generated technically (X-ray radiation) or arise when certain atomic nuclei decay radioactively (alpha, beta, gamma and neutron radiation). When certain atomic nuclei transform themselves into other nuclei without external influence and emit high-energy radiation (ionizing radiation), this property is called radioactivity. The process of nuclear transformation is known as radioactive decay. The radioactive atomic nuclei are called radionuclides.

Even if atomic nuclei are fissioned, for example in the fuel rods of a nuclear reactor, ionizing radiation is generated in addition to the fission products.

Depending on the starting material, stable or radioactive decay products are created during radioactive decay. The radioactive decay products continue to decay. Radioactive substances emit ionizing radiation until the "last" radionuclide has decayed.

Alpha radiation collapse / expand

Alpha radiation is particle radiation that consists of two protons and two neutrons. An alpha particle is therefore a nucleus of the element helium. Alpha particles are absorbed very quickly by matter (e.g. air or water) and therefore only have a very short range (a few centimeters in air; less than a millimeter in water). They can already be shielded by a sheet of paper.

When exposed to the outside world, alpha radiation can only penetrate into the outer layers of the human skin. If alpha emitters, i.e. radioactive substances that emit alpha particles when they decay, enter the body via the air or food (incorporation), this can lead to considerable radiation exposure. Since the alpha particles emit their energy over a very short distance, they damage the tissue particularly severely.

A typical and important example of the incorporation of alpha emitters is the absorption of radon and its secondary products with the air we breathe.

Beta radiation collapse / expand

Beta radiation is particle radiation that occurs when radioactive atomic nuclei emit (negatively charged) electrons or - less often - positrons (particles that have the same mass as electrons but are positively charged) when they decay. Beta radiation is less strongly absorbed by matter than alpha radiation and therefore has a greater range: The penetration capacity of beta particles is a few centimeters to meters in air and a few millimeters to centimeters in soft tissue or plastic. Beta radiation can be shielded relatively easily, for example with an aluminum sheet that is a few millimeters thick.

Radioactive particles that emit beta radiation can also lead to considerable radiation exposure if they are absorbed (incorporated) into the body with the air we breathe or with food. Beta radiation, which acts on the body from outside, can also damage the tissue because it can penetrate the body, albeit not very deeply. However, over a certain distance it emits significantly less energy than alpha radiation. It is said that beta radiation has a lower biological effectiveness than alpha radiation.

Neutron radiation collapse / expand

Neutron radiation consists of uncharged particles (the neutrons). Neutrons are released in particular during nuclear fission - a special form of nuclear transformation. Nuclear fission is only characteristic of heavy atomic nuclei (such as the element uranium).

Neutron radiation is hardly absorbed by air. Their shielding is quite complex. Materials with the highest possible hydrogen content (for example paraffin, polyethylene, water) are used to initially slow down the neutrons. The decelerated (thermal) neutrons must be captured by an absorber (for example boron or cadmium). The gamma radiation released at the same time must be shielded with lead.

Mainly due to the strong interaction with biological tissue (especially the water molecules it contains), neutron radiation has a high biological effectiveness.

Gamma radiation collapse / expand

With gamma radiation, energy is transported as an electromagnetic wave. The electromagnetic radiation can be described in terms of its frequency or its wavelength. The higher the frequency and the shorter the wavelength, the more energetic the radiation. Gamma radiation is at the high-energy end of the "electromagnetic spectrum", at a high frequency or a short wavelength.

Gamma radiation is created when radioactive atoms decay in the atomic nucleus, often in addition to alpha or beta radiation. It penetrates matter very easily. Their shielding is therefore complex. Heavy materials such as lead and concrete are used for this.

Gamma radiation is harmful to living beings, both when exposed to the outside and when incorporated, since it penetrates deep into the tissue. However, their biological effectiveness is lower than that of alpha radiation, for example, as it emits less energy to the tissue over a certain distance.

X-rays collapse / expand

X-rays are electromagnetic radiation. It can be generated technically when fast electrons are slowed down at the anode (positively charged electrode) of an X-ray tube. The higher the applied tube voltage with which the electrons are accelerated in the X-ray tube, the shorter-wave and therefore more energetic is the maximum energy of the resulting X-ray radiation.

When the X-ray machine is switched off, no X-ray radiation is generated.

X-rays can also arise as a result of the decay of radioactive atomic nuclei, when the chemical element changes as a result of the decay. The electron shell adapts to this change and emits the energy released in the form of X-rays.