Associate Safety Professional Practice Exam

What types of ionizing radiation can a Geiger-Mueller radiation measuring instrument detect?

1. Only alpha rays

2. Gamma, beta, and alpha rays

3. Only gamma rays

4. Beta and X-rays

The correct answer is: Gamma, beta, and alpha rays

A Geiger-Mueller radiation measuring instrument is designed to detect various types of ionizing radiation, which includes gamma rays, beta particles, and alpha particles. When you consider the construction and functioning of the Geiger-Mueller tube, it operates by ionizing the gas within the tube when radiation passes through it. This ionization leads to a measurable electric current, which is counted and displayed. Gamma rays are highly penetrative electromagnetic radiation, and the Geiger-Mueller instrument is sensitive to these rays due to their ability to interact with the gas in the tube and produce ions. Similarly, beta particles, which are negatively or positively charged particles emitted from certain radioactive decays, also interact with the Geiger-Mueller tube medium, allowing for detection. Furthermore, while alpha rays have a limited range and are not as penetrative as gamma and beta radiation, Geiger-Mueller instruments can still detect them, but they require the radiation source to be relatively close due to the limited travel distance of alpha particles in air. This capability to detect all three types—alpha, beta, and gamma—makes the Geiger-Mueller tube a versatile instrument in radiation safety and monitoring, providing critical information for safety professionals dealing with radioactive materials.