ASNT Industrial Radiography Radiation Safety Practice Test

Why are gases bombarded by ionizing radiation useful in detection equipment?

1. They absorb light

2. They become conductors of electrical current

3. They emit sound

4. They change color

The correct answer is: They become conductors of electrical current

Gases bombarded by ionizing radiation are useful in detection equipment primarily because they become conductors of electrical current. When ionizing radiation interacts with the gas molecules, it can ionize them, causing the gas to produce free electrons and positive ions. This process allows the gas to conduct electricity, making it possible for detection equipment to measure the presence and intensity of radiation. In devices such as gas ionization chambers or Geiger-Müller tubes, the resulting ionization creates a measurable electrical current when a high voltage is applied across the gas. This current is then amplified and recorded, providing a real-time indication of radiation levels. The ability of ionized gases to act as conduits for electrical current is foundational to the function of many radiation detection instruments, enabling accurate and reliable measurements of radiation exposure. This phenomenon is essential for maintaining safety and monitoring radiation levels in various industrial and medical environments.