Dosimeter
device that measures exposure to ionizing radiation From Wikipedia, the free encyclopedia
A dosimeter is a tool that can measure different levels of hazardous environments. Common dosimeters are those used for sound (They measure how loud a certain noise is) and radiation (they measure how much radiation there is in an environment).

There are many uses for dosimeters. For example, workers in nuclear power plants use them to track their radiation exposure. Doctors, especially ones using X-rays, use them too.
Related pages

Wikimedia Commons has media related to Dosimeters.
Wikiwand - on
Seamless Wikipedia browsing. On steroids.