radioactive substances and the emanating from it radiation are often associated with danger. But did you know that they are used to fight the same disease they cause? One of the three known types of radiation is the so-called beta radiation. But what exactly is beta radiation, which species are there and which ones Characteristics has she?
beta decay
Radioactive decay comes up particularly often unstable isotopes of an element. elements are defined by their number of protons in the nucleus, while their number of neutrons can vary. You name atoms with the same number of protons but a different number of neutrons isotopes.
You can find more about the isotopes in the explanation of the same name.
Different isotopes have different levels of energetic stability and can therefore undergo radioactive decay processes to become one energetically more favorable state to get. Such a decay process is the beta decay.
At the beta decay an isotope goes into a by conversions of a neutron into a proton (or vice versa). more favorable energy state about, where radiation becomes free.
You can read everything you need to know about beta decay in the explanation of alpha and beta decay.
You distinguish two types of beta decay: the Beta Plus Decay and the Beta minus decaywhereby beta radiation is released in each case.
Beta radiation simply explained
In general, beta radiation is radiation that is released as a result of radioactive decay ionizing radiation. This is able to release electrons from other atoms or molecules. The three different types of radiation are named after the respective decay processes in which they arise.
as beta radiation do you indicate the type of ionizing particle radiationwho at radioactive beta decay formed by atomic nuclei. A radioactive isotope that emits beta radiation is also called a beta emitter.
In everyday life, such ionizing radiation as beta radiation is sometimes referred to as radioactive radiation. However, the radiation itself is not radioactive, only the atom that emits it. You can find everything about ionizing radiation in the explanation of the same name.
Just like alpha radiation, beta radiation is made up of high energy particleswhich you also as beta particle designate On the other hand, it is the gamma radiation around electromagnetic waves. You can find out more about this in the statement on gamma radiation.
It is important to distinguish that beta radiation and beta decay are not identical: beta decay is a processwhich an atom can pass under certain conditions. beta radiation is this productthat arises. Just as there are two different beta decays, there are also two different types of beta radiation, each with an associated one decay equation.
Beta minus radiation
Beta minus radiation arises during the radioactive decay of isotopes with a high number of neutrons compared to the number of protons in the nucleus. You speak of one relative neutron excess. These isotopes can transition to an energetically more favorable state by converting a neutron into a proton.
as Beta minus radiation (\(\beta^-\)- radiation) you designate the ionizing radiationwho are in the process of Beta minus decay arises. It consists of an electron \( e^-\) and an electron antineutrino \(\overline \nu_{e}\). The associated decay equation is:
\(\ce{^{A}_{Z}X -> ^{A}_{Z+1}Y + e^- + \overline{\nu_{e}}}\)
By converting a neutrons \(n\) in a proton \(p\) in \(\beta^-\)-decay, the mass number \(A\) of the isotope \(\ce{^{A}_{Z}X}\) is preserved, while the atomic number \(Z\) is increased by 1. This creates a new element \(\ce{^{A}_{Z+1}Y}\).
You can find a detailed description and concrete examples of the decay equation in the explanation of alpha and beta decay.
That Electron Antineutrino is the antimatter partner to the electron neutrino, which together with the electron forms the first generation of the particle class leptons. You can find more about the leptons in the explanation of the same name.
You can see the release of the beta-minus radiation illustrated on the atomic level in the following figure.
The «minus» in the name of radiation comes from the negative electrical charge of the emitted electron.
The opposite of beta minus radiation is beta plus radiation.
Beta Plus Radiation
the Beta Plus Radiation takes its name from the positive charge of the positron, which is emitted instead of the electron in this type of decay. The positron is the antimatter partner to the electron. So it owns same massbut one opposite electric charge. In addition, a electron neutrino free.
as Beta Plus Radiation (\(\beta^+\)- radiation) you designate the ionizing radiationwho are in the process of Beta Plus Decay arises. It consists of one positron \( e^+\) and one electron neutrino \(\nu_{e} \). The associated decay equation is:
\(\ce{^{A}_{Z}X -> ^{A}_{Z-1}Y + e^+ + \nu_{e}}\)
By converting a protons \(p\) into a neutron \(n\) in \(\beta^+\)-decay, the mass number A of the isotope \(\ce{^{A}_{Z}X}\) is preserved, while the atomic number Z is reduced by 1. This creates a new element \(\ce{^{A}_{Z-1}Y}\) .
This type of radiation occurs mainly in isotopes with a high number of protons compared to the number of neutrons (relative proton excess). The atom moves to a more favorable energy state by converting a proton into a neutron. At the atomic level, you can think of it like this:
Beta radiation has specific properties in which it also differs from other types of radiation.
Beta Radiation Properties
Energy is released during beta decay. The energy of the emitted beta radiation depends heavily on the isotope undergoing beta decay. The following table shows you the different ones maximum energieswhich the emitted radiation has when the respective isotope decays.
isotope symbol-notationdecay typemax. Energy in keVTritium\(^3{H}\)\(\beta^-\)18.59Sulphur\(^{35}{S}\)\(\beta^+\)167Calcium\(^{45}{ Ca}\)\(\beta^+\)257Carbon\(^{11}{C}\)\(\beta^+\)960.4Bismuth\(^{210}{Bi}\)\(\beta ^-\)1162.2
The table shows you the maximum energy of beta radiation. In reality, this energy varies greatly; on average, most beta particles have about a third of the maximum possible energy.
beta radiation speed
A large part of the energy of the beta radiation is in the kinetic energy (kinetic energy) of the beta particles. Yours can do the same speed vary greatly.
Because the electron (and positron) have a much smaller mass than, for example, the alpha particle, they can be greatly accelerated upon emission. Your speed can even values close to the speed of light accept. The same applies to the almost massless neutrino (and antineutrino).
Beta radiation is usually faster than alpha radiation, but slower than gamma radiation.
Beta radiation range shielding
Also the Range of beta radiation is greater than that of the alpha particle. However, alpha radiation is more ionizing because the alpha particles are much larger than the beta particles and therefore collide with the particles in matter more often.
When ionizing radiation passes through a medium, such as air, it collides with the particles it contains and (partly) transfers its energy to them. The particles in the medium are ionized while the beta particles are slowed down or slowed down completely.
as Range do you designate them distancethe particle radiation travels until it has its kinetic energy completely released (by ionization). Has. The range depends on the kind of the particles, their original energy and the surrounding medium.
Some materials are therefore better at shielding from beta radiation than others because the beta particles in them travel less far before they have used up all their energy. You can see how far beta radiation with a certain energy can reach in different media in the following table:
Energy in keVRange in airRange in tissueRange in aluminum103 mm0.0025 mm0.009 mm1000.1 m0.16 mm0.05 mm5001.2 m1.87 mm0.6 mm10003.06 m4.75 mm1.52 mm20007.10 m11.1 mm4, 08mm
Accordingly, a thin layer of aluminum is usually sufficient to shield even high-energy beta radiation.
radiation effect
As you can see in the table from the previous section, energetic beta radiation can penetrate a few millimeters deep into the tissues of an organism. With that she can upper layers of skin damage and cause burns. At higher radiation dose can high-energy beta particles die DNA in the cell nuclei and in the long term skin cancer to lead. Prolonged exposure to intense beta radiation can lead to loss of vision.
It is even more critical if beta radiation, for example via food, into the body reached. There it can also damage the cells of various organs. For example, radioactive iodine-130 can build up in the thyroid gland or strontium-90 in the bones. The consequences can be thyroid cancer and leukemia.
You can find more on this topic in the explanation of the biological effects of radiation.
Paradoxically, the damaging effects of beta radiation can also contribute to tumor control be used. In the so-called radiotherapy become beta particles, along with other ionizing radiation, fired specifically at the cancerous tissue. This will make the cancer cells destroyed. It is important with this therapy that no healthy tissue comes into contact with the radiation.
Beta Radiation – The Most Important
- At the beta decay an isotope goes into a by conversions of a neutron into a proton (or vice versa). more favorable energy state about, where radiation becomes free.
- as beta radiation do you indicate the type of ionizing particle radiationwho at radioactive beta decay formed by atomic nuclei. You differentiate between beta plus radiation and beta minus radiation.
- A radioactive isotope that emits beta radiation is also called a beta emitter.
- as Beta minus radiation (\(\beta^-\)- radiation) you designate the ionizing radiationwho are in the process of Beta minus decay arises. It consists of an electron \( e^-\) and an electron antineutrino \(\overline \nu_{e}\).
- In beta minus decay, a neutron is converted into a proton. The associated decay equation is:
\(\ce{^{A}_{Z}X -> ^{A}_{Z+1}Y + e^- + \overline{\nu_{e}}}\)
- as Beta Plus Radiation (\(\beta^+\)- radiation) you designate the ionizing radiationwho are in the process of Beta Plus Decay arises. It consists of one positron \( e^+\) and one electron neutrino \(\nu_{e}\).
- At the Beta Plus Decay a proton becomes a neutron. The associated decay equation is:
\(\ce{^{A}_{Z}X -> ^{A}_{Z-1}Y + e^+ + \nu_{e}}\)
- The properties of beta radiation, like theirs speed and Rangemainly depend on the (kinetic) energy of…