Rd
rutherford
Radioactivityexact by definition
The rutherford is exactly 10⁶ Bq, defined as one million disintegrations per second. It was proposed in 1946 as a decimal alternative to the curie, sized to be a practical laboratory quantity rather than the activity of a gram of radium.
| 1 Rd | 1,000,000 Bq |
Where the unit came from
Named for Ernest Rutherford and used in the 1950s and 1960s, mostly in British and French radiochemistry, before the becquerel superseded it in 1975. It is genuinely obsolete, and included here so that mid-century papers can be read without a conversion table.
Solvers that use radioactivity