Applications
Ionizing radiation, such as X-rays, alpha rays, beta rays, and gamma rays, are undetectable by the human senses, therefore a measuring device is used to detect, measure and record this, and in some cases give an alarm when a preset level is exceeded. Ionising radiation damage to the body is cumulative, and is related to the total dose received, for which the SI unit is the Sievert. Therefore, workers exposed to radiation, such as radiographers, nuclear power plant workers, doctors using radiotherapy, those in laboratories using radionuclides, and some HAZMAT teams are required to wear dosimeters so their employers can keep a record of their exposure to verify that it is below legally prescribed limits. Such devices are known as "legal dosimeters", meaning that they have been approved for use in recording personnel dose for regulatory purposes.
Crew members aboard NASA Space Shuttle missions had access to four types of active dosimeters should a radiation contingency occur. Crew members were required to wear passive dosimeters at all times throughout the mission.
Read more about this topic: Dosimeter