The rutherford (symbol Rd) is a non-SI unit of
radioactive decay
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...
. It is defined as the
activity of a quantity of radioactive material in which one million
nuclei decay per
second
The second (symbol: s) is a unit of time derived from the division of the day first into 24 hours, then to 60 minutes, and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of U ...
. It is therefore equivalent to one
megabecquerel, and one becquerel equals one microrutherford. One rutherford is equivalent to
curie, or rutherfords for one curie.
The unit was introduced in 1946.
It was named after British/New Zealand physicist and Nobel laureate
Lord Ernest Rutherford (Nobel Prize in 1908),
who was an early leader in the study of
atomic nucleus
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford at the Department_of_Physics_and_Astronomy,_University_of_Manchester , University of Manchester ...
disintegrations. After the becquerel was introduced in 1975
as the SI unit for activity, the rutherford became obsolete, and it is no longer commonly used.
Radiation related quantities
The following table shows radiation quantities in SI and non-SI units:
References
Units of radioactivity
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