The rutherford (symbol Rd) is a non-SI unit of radioactive decay.
It is defined as the activity of a quantity of radioactive material in which one million nuclei decay per second.
[1] It was named after British/New Zealand physicist and Nobel laureate Lord Ernest Rutherford (Nobel Prize in 1908),[2] who was an early leader in the study of atomic nucleus disintegrations.
After the becquerel was introduced in 1975[3] as the SI unit for activity, the rutherford became obsolete, and it is no longer commonly used.
The following table shows radiation quantities in SI and non-SI units: