Proton attachment
Proton attachment (also called proton capture ) is a nuclear reaction in which a proton is added to an atomic nucleus , whereby only gamma radiation is emitted. This type of nuclear reaction is written in a formula .
The cross section of the reaction is strongly influenced by the charge of the atomic nucleus to which the proton is to be added. Since the approaching proton, like the atomic nucleus, is positively charged, it is first repelled. The charge of the atomic nucleus, i.e. h. to which chemical element is, therefore, determines how much momentum the proton must have in order to Coulombwall overcome and the nucleus close enough for capture.
Proton attachment plays an important role in astrophysics . When hydrogen burns inside stars , reactions occur both in the proton-proton chain and in the CNO cycle . Proton captures also generate proton-rich atomic nuclei in further burning phases of stars. At very high temperatures and a high number of protons per volume ( proton density ), the p-process or rapid proton capture processes can also take place, which generate extremely proton-rich nuclides and radionuclides (see p-nuclei ).
Technically, the proton attachment reaction by means of a cyclotron is used to produce radionuclides for medical purposes. The nuclides produced in this way are positron emitters (see beta plus decay ). They are needed as tracers and for positron emission tomography .
See also
Individual evidence
- ^ Heinz Oberhummer : Cores and Stars. (Barth, 1993)
- ↑ T. Rauscher, A. Patkós: Origin of the Chemical Elements. In: Handbook of Nuclear Chemistry, 2nd edition (Springer, 2011), Volume 2, Chapter 1. ISBN 978-1-4419-0721-9 , arxiv : 1011.5627 , online
- ↑ TF Budinger, HF VanBrocklin: Positron Emission Tomography (PET). In: The Biomedical Engineering Handbook, Second Edition (CRC Publishing, 1999), Chapter 67. ( ISBN 978-0-8493-8594-0 , online )