|Physical quantity (s)||Cross section|
|In SI units|
|Named after||English barn , "barn"|
|Derived from||square meters|
- 1 b = 10 −24 cm 2 = 10 −28 m 2 .
Common decimal parts
Small cross-sections are given in millibarn (mb), microbarn (µb), nanobarn (nb) or picobarn (pb). For example is
- 1 pb = 10 −12 b = 10 −40 m 2 .
The unit shed was intended to describe very small cross- sections, especially of neutrino reactions, but it never really caught on. It applies
- 1 shed = 10 −24 b = 10 −52 m 2 .
The designation barn for the already common cross section unit 10 −24 cm 2 was introduced in December 1942 by two scientists from Purdue University who were involved in the US nuclear weapons development ( Manhattan Project ). It played a role that an effective cross-section of this size for nuclear reactions “ as big as a barn ” (German: “big as a barn door”) appeared.
- The International System of Units (SI) . German translation of the BIPM brochure "Le Système international d'unités / The International System of Units (8e edition, 2006)". In: PTB-Mitteilungen . tape 117 , no. 2 , 2007, p. 156 ( hs-heilbronn.de [PDF; 1.4 MB ]). Online version (PDF; 1.4 MB) ( Memento from March 4, 2016 in the Internet Archive )
- Nuclear Glossary
- MG Holloway, CP Baker: How the barn was born. In: Physics Today , July 1972