AQA GCSE FOUNDATION PHYSICS - Radioactive Decay and Types of Radiation

Radioactive Decay and Types of Radiation

Introduction

Radioactive decay is a process where unstable atomic nuclei release energy and particles to become more stable. This process emits radiation, which can be harmful to living organisms. We'll delve into the three main types of radiation: alpha, beta, and gamma.

Alpha Radiation

• What it is: Alpha radiation consists of two protons and two neutrons bound together, essentially a helium nucleus (?He).
• Properties:
  • Charge: +2
  • Mass: 4 atomic mass units (amu)
  • Penetration: Low, stopped by a sheet of paper or even a few centimeters of air.
  • Ionizing power: High, interacts strongly with matter, causing significant ionization.
• Examples:
  • Uranium-238 decays into Thorium-234 by emitting an alpha particle.
  • Plutonium-239 decays into Uranium-235 by emitting an alpha particle.

Beta Radiation

• What it is: Beta radiation is the emission of an electron (??) or a positron (??) from the nucleus.
• Properties:
  • Beta-minus (??):
    • Charge: -1
    • Mass: Negligible compared to protons and neutrons
    • Penetration: Medium, stopped by a thin sheet of aluminum or a few millimeters of plastic.
    • Ionizing power: Medium, interacts with matter less strongly than alpha radiation.
  • Beta-plus (??):
    • Charge: +1
    • Mass: Negligible compared to protons and neutrons
    • Penetration: Medium, stopped by a thin sheet of aluminum or a few millimeters of plastic.
    • Ionizing power: Medium, interacts with matter less strongly than alpha radiation.
• Examples:
  • Carbon-14 decays into Nitrogen-14 by emitting a beta-minus particle.
  • Potassium-40 decays into Argon-40 by emitting a beta-minus particle.

Gamma Radiation

• What it is: Gamma radiation is a high-energy electromagnetic wave, similar to X-rays but with even higher energy.
• Properties:
  • Charge: None
  • Mass: None
  • Penetration: High, can penetrate several centimeters of lead or concrete.
  • Ionizing power: Low, interacts weakly with matter, causing less ionization than alpha or beta radiation.
• Examples:
  • Cobalt-60 emits gamma rays during its radioactive decay.
  • Iodine-131 emits gamma rays during its radioactive decay.

Summary

Note: Radioactive decay is a random process. We can't predict when a particular atom will decay, but we can predict the rate of decay for a large sample.

Applications

Radioactive isotopes have various applications in medicine, industry, and research, including:

• Medical imaging: Radioisotopes are used in diagnostic imaging techniques like PET scans.
• Cancer treatment: Radioactive isotopes are used in radiation therapy to kill cancerous cells.
• Industrial processes: Radioactive isotopes are used to trace the flow of materials in pipelines and to measure the thickness of materials.
• Archaeological dating: Carbon-14 dating is used to determine the age of ancient artifacts.

Hazards

Radioactive radiation can be harmful to living organisms. Exposure to high levels of radiation can cause tissue damage, radiation sickness, and even death. It's crucial to handle radioactive materials safely and to minimize exposure.

Conclusion

Radioactive decay and its associated radiation play a crucial role in various scientific and technological applications. Understanding the different types of radiation and their properties is essential for safely utilizing and managing radioactive materials.