Lecture Notes: Types of Nuclear Radiation

Introduction to Isotopes and Radioactive Decay

• Isotopes: Variants of an element with the same number of protons but different neutrons.
  • Most elements have one or two stable isotopes, the rest are unstable.
• Radioactive Decay: The process by which unstable isotopes emit particles to become more stable.
• Radioactive Materials: Composed of unstable isotopes capable of decay.

Types of Nuclear Radiation

• Four Main Types: Alpha particles, Beta particles, Gamma rays, and Neutrons.
• Each type varies in ionizing ability and penetration capacity.

Alpha Radiation

• Composition: Made up of 2 protons and 2 neutrons (like helium nucleus, He).
• Charge: +2 (two positive protons, no electrons).
• Penetration: Limited; can be stopped by a few centimeters of air or a single sheet of paper.
• Ionizing Ability: Strong; effectively knocks electrons off atoms due to large size and charge.

Beta Radiation

• Composition: Electrons with a charge of -1 and negligible mass.
• Emission Process: Neutron decays into a proton and an electron; electron is emitted.
• Penetration: Moderate; requires several meters of air or about 5 mm of aluminum to stop.
• Ionizing Ability: Moderate due to smaller size.

Gamma Radiation

• Nature: Electromagnetic waves, not particles.
• Emission: Often follows alpha or beta decay, enabling the nucleus to release excess energy.
• Penetration: High; penetrates far into materials, requiring thick lead or meters of concrete to stop.
• Ionizing Ability: Weak due to lack of mass and charge.

Neutron Emission

• Purpose: Emission occurs when a nucleus has excess neutrons, enhancing stability.

Recap

• Alpha Particles: Stopped by paper, highly ionizing.
• Beta Particles: Stopped by thin aluminum, moderately ionizing.
• Gamma Rays: Require thick lead to stop, weakly ionizing.

• Conclusion: Understanding of nuclear radiation types, their characteristics, and effects.