bild

Personal radiation monitor on a person's finger. This is an extremity TLD (thermoluminescent dosimeter). It is worn by people who are exposed to radiation regularly during their work. A piece of plastic within the dosimeter becomes pitted when hit by radiation. The number of pits is proportional to the amount of radiation allowing a person's daily exposure to be calculated. (KEYSTONE/SCIENCE PHOTO LIBRARY/HEALTH PROTECTION AGENCY)