Rutherford (unit)

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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. It is therefore equivalent to one megabecquerel, and one becquerel equals one microrutherford. One rutherford is equivalent to 2.703 × 10−5 curie.

The unit was introduced in 1946.[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.


  1. ^ Lind, SC (1946), "New units for the measurement of radioactivity", Science, 103 (2687): 761–762, doi:10.1126/science.103.2687.761-a, PMID 17836457. 
  2. ^ "The Nobel Prize in Chemistry 1908". 
  3. ^ Harder, D (1976), "[The new radiologic units of measurement gray and becquerel (author's translation from the German original)]", Röntgen-Blätter, 29 (1): 49–52, PMID 1251122.