Hazardous Materials 6th Edition Practice Test 2026 - Free Hazardous Materials Practice Questions and Study Guide

Neutron radiation is the emission of a neutron from the nucleus, and it’s effectively stopped by hydrogen-rich materials like concrete or water. The key reason is how neutrons interact with matter: they are uncharged and slow down mainly through collisions with nuclei. When a fast neutron hits hydrogen (a proton), it transfers a large portion of its energy because the masses are similar, so it loses energy quickly and becomes a slow, or thermal, neutron. Slower neutrons are more likely to be captured, which further reduces their ability to penetrate. That’s why materials rich in hydrogen—such as concrete and water—are excellent neutron shields. In contrast, gamma rays are photons and are best shielded by dense, high-atomic-number materials; alpha particles are stopped by a sheet of paper or skin; beta particles require plastics or thin metals.