Mache (unit)
Introduction '''Mache''' (symbol '''ME''' from German Mache-Einheit, plural Maches) is a unit of volumic radioactivity named for the Austrian physicist Heinrich Mache. It was defined as the quantity of radon (ignoring its daughter isotopes; in practice, mostly radon-222) per litre of air which ionises a sustained current of 0.001 esu (0.001 StatAmpere).1 ME = 3.64 Eman = 3.64×10−10 Ci/L = 13.4545 Bq/L.
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