Well counter

A well counter is a device used for measuring radioactivity in small samples. It usually employs a sodium iodide crystal detector. It was invented in 1951 by Hal Anger, who is also well known for inventing the scintillation camera. Anger filed U.S. patent #2,779,876 on March 3, 1953 for his "Radio-Activity Distribution Detector" which was later issued on January 29, 1957.