Background Radiation (OCR GCSE Physics A (Gateway Science Suite)): Revision Notes

4.3.1 Background Radiation

Background Radiation (Physics Only)

Sources

• Cosmic Rays: High-energy particles from outer space that reach the Earth.

• Radiation from Underground Rocks: Naturally occurring radioactive materials, such as radon gas, emitted from rocks and soil.

• Nuclear Fallout: Residual radioactive material from nuclear weapons testing or accidents.

  

• Medical Rays: Radiation from medical procedures, such as X-rays and radiation therapy.

Factors Affecting Background Radiation

Occupation: Certain jobs, like those in healthcare or nuclear industries, expose workers to higher levels of radiation.

Location: Areas with higher natural radiation levels, such as those with radon gas, or proximity to nuclear facilities, can affect radiation exposure.

Measurement

Radiation Dose: The amount of radiation absorbed by the body, measured in Sieverts (Sv).

Types of Radiation

Alpha Radiation

• Characteristics:
  • Strongly Ionising: Alpha particles can easily ionise nearby atoms, causing damage.
  • Low Penetration: Alpha particles are stopped by dead skin cells and cannot penetrate the skin, but are hazardous if inhaled or ingested.

Beta Radiation

• Characteristics:
  • Moderately Ionising: Beta particles can ionise atoms, but less so than alpha particles.
  • Medium Penetration: Beta particles can penetrate the skin and enter the body, posing a risk to internal organs.

Gamma Radiation

• Characteristics:
  • Weakly Ionising: Gamma rays have a lower ionising power compared to alpha and beta particles.
  • High Penetration: Gamma rays can penetrate deep into the body and materials but are less likely to cause ionisation within the body.

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