It is also used where radiation is unexpected, such as in the aftermath of the Three Mile Island, Chernobyl or Fukishima radiological release incidents, where the public dose is measured and calculated from a variety of indicators such as ambient measurements of radiation and radioactive contamination.
The sievert is of fundamental importance in radiation dosimetry, and is named after Rolf Maximilian Sievert, a Swedish medical physicist renowned for work on radiation dosage measurement and research into the biological effects of radiation.