Rutherford (unit)

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.

rutherford
Unit ofActivity
SymbolRd
Named afterLord Ernest Rutherford
Conversions
1 Rd in ...... is equal to ...
   curie   2.703×10−5 Ci
   SI derived units   1 MBq
   SI base units   106 s−1

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.

The following table shows radiation quantities in SI and non-SI units:

Ionizing radiation related quantities
QuantityUnitSymbolDerivationYearSI equivalence
Activity (A) becquerel Bq s−1 1974 SI unit
curie Ci 3.7 × 1010 s−1 1953 3.7×1010 Bq
rutherford Rd 106 s−1 1946 1,000,000 Bq
Exposure (X) coulomb per kilogram C/kg C⋅kg−1 of air 1974 SI unit
röntgen R esu / 0.001293 g of air 1928 2.58 × 10−4 C/kg
Absorbed dose (D) gray Gy J⋅kg−1 1974 SI unit
erg per gram erg/g erg⋅g−1 1950 1.0 × 10−4 Gy
rad rad 100 erg⋅g−1 1953 0.010 Gy
Equivalent dose (H) sievert Sv J⋅kg−1 × WR 1977 SI unit
röntgen equivalent man rem 100 erg⋅g−1 x WR 1971 0.010 Sv
Effective dose (E) sievert Sv J⋅kg−1 × WR x WT 1977 SI unit
röntgen equivalent man rem 100 erg⋅g−1 x WR x WT 1971 0.010 Sv


References
  1. Lind, SC (1946), "New units for the measurement of radioactivity", Science, 103 (2687): 761–762, Bibcode:1946Sci...103..761L, 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.


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