US Civil Defense Rad Counter/Pocket Dosimeter Pen

The US Civil Defense Rad Counter, commonly known as a pocket dosimeter pen, is a compact, analog radiation detection device designed for personal monitoring of cumulative exposure to ionizing radiation. Widely issued during the Cold War era, particularly in the 1950s and 1960s, these dosimeters were distributed to civil defense personnel, emergency responders, and military members for use in nuclear event preparedness and response. The cylindrical instrument is typically constructed from durable metal and features a small window or eyepiece for reading measured radiation levels, marked in roentgens. Operation involves zeroing the device with a charging unit before use, and it provides continuous, real-time readings without requiring external power sources. Pocket dosimeters such as this model were an essential part of US civil defense equipment, serving as an early warning tool in environments with potential radioactive contamination. These items retain historical significance as artifacts of mid-20th century nuclear defense measures.