Film badge dosimeter

The device was developed by Ernest O. Wollan whilst working on the Manhattan Project,[3] though photographic film had been used as a crude measure of exposure prior to this.

To monitor gamma rays or x-rays, the filters are metal, usually lead, aluminum, and copper.

Normally it is worn at chest height under a lead apron to measure the radiation level the entire body has received.

The badge is typically worn on the outside of clothing, around the chest or torso to represent dose to the "whole body".

This location monitors exposure of most vital organs and represents the bulk of body mass.

Additional dosimeters can be worn to assess dose to extremities or in radiation fields that vary considerably depending on orientation of the body to the source.