This article is about Geiger counters and ion-chamber instruments, and it uses the term "Geiger counter" as a colloquial name for any hand-held radiation measuring device in civil defense. However, most civil defense devices were ion-chamber radiological survey meters capable of measuring only high levels of radiation that would be present after a major nuclear event. Most Geiger and ion-chamber survey meters were issued by governmental civil defense organizations in several countries from the 1950s in the midst of the Cold War in an effort to help prepare citizens for a nuclear attack.
