Counts per minute
Counts per minute (abbrev. CpM, or more accurately Cpm) was a measurement used to determine the amount of ion radiation was present. Such a measurement could be determination by an ion trace scan.

The weapons analysis made by Malcolm Reed of the the debris of a  that was discovered by  in late 2154 determined that the amount of ion radiation in the area was 569 CpM. This was one of the indicators that confirmed a Klingon weapon signature. ( display readout)

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Radiation
Measurements