NMTCB Radiation Safety Practice Exam

Alpha particles have the highest ionizing power among the types of radiation listed. Ionizing radiation is categorized based on its ability to remove tightly bound electrons from atoms, which can lead to the formation of ions.

Alpha particles, which are composed of two protons and two neutrons, carry a positive charge and are relatively large compared to beta particles, x-rays, and gamma rays. Due to their mass and charge, alpha particles have a strong interaction with matter, resulting in a higher probability of ionizing atoms they encounter. This strong interaction allows alpha particles to cause significant ionization over a very short distance—typically just a few centimeters in air and a fraction of a millimeter in human tissue.

In contrast, beta particles, x-rays, and gamma rays have lower ionizing power because they are either lighter (beta particles) or non-particulate (x-rays and gamma rays). While beta particles can also cause ionization, their capacity is less than that of alpha particles because they are less massive and carry either a negative or no charge. X-rays and gamma rays, being forms of electromagnetic radiation, have minimal interaction with matter and thus exhibit a much lower level of ionizing power compared to alpha particles.

The high ionizing power of