Wiktionary
film badges
n. (plural of film badge English)
Usage examples of "film badges".
You see, the radiation film badges showed contamination, but the engine room instruments did not.
They also passed a few other people, each wearing cylindrical dosimeters that served the same purpose but looked nothing like the film badges everyone sported at CERN.
But in the movies you saw on TV, the men who handled radioactive stuff were always wearing those protective suits and film badges that turned color if you got a dose.