Richard Born at Northern Illinois University developed an experiment for determining the efficiency of a Geiger-Müller (G-M) tube using the new Vernier Radiation Monitor.
The Radiation Monitor is mounted on a wooden stand, and the radioactive source is mounted a set distance from the G-M tube end window. Radiation counts are collected for ten one-minute intervals each for background, Sr-90, and Co-60. By using the number of detected counts for the radiation source and the known number of radiation disintegrations from the source, students can calculate the efficiency of the G-M tube.
Download Richard’s lab instructions for determining the efficiency of a Geiger-Müller tube