Counts per minute
1035712
206592299
2008-04-18T23:29:17Z
TheVaultDweller
5353431
{{otheruses4|radioactivity|other uses of abbreviation|CPM}}
{{otheruses4|radioactivity|other uses of abbreviation|DPM}}
'''Counts per minute (cpm)''' is a measure of [[radioactivity]]. It is the number of [[atom]]s in a given quantity of radioactive material that are ''detected'' to have decayed in one minute. '''Disintegrations per minute (dpm)''' is also a measure of radioactivity. It is the number of atoms in a given quantity of radioactive material that decay in one minute. Dpm is similar to cpm, however the efficiency of the [[radiation detector]] (e.g. [[scintillation counter]]) must be accounted for when analysing data in cpm. Dpm is the number of atoms that have decayed, not the number of atoms that have been measured as decayed. Dpm is commonly used as a measure of [[radioactive contamination]].
* One [[becquerel]] (Bq) is equal to one disintegration per second, or 60 dpm.
* One [[curie]] (Ci) is equal to 3.7 x 10 <sup>10</sup> Bq or dps, which is equal to 2.22 x 10<sup>12</sup> dpm.
[[Category:Units of radioactivity]]
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[[ja:壊変毎分]]