Rutherford (unit)
The rutherford (symbol Rd) is a non-SI unit of radioactivity, defined as the activity of a quantity of radioactive material in which one million nuclei decay per second.
1 Rd = 106 disintegrations per second = 106 Bq (becquerels) = 1 mBq (millibecquerel) = approximately 27.027 microcuries.
The unit was named after physicist Ernest Rutherford. While proposed as a unit of activity, it is not widely used in scientific literature today, with the becquerel (Bq), the SI unit of activity, being preferred. The curie (Ci) is another non-SI unit of activity that is occasionally encountered.