Background Radiation

• What is background radiation defined as?

  The ionising radiation present in the environment
• What are the sources of background radiation?

  • Natural sources
  • Artificial sources
• What is the largest source of background radiation in the UK?

  Radon gas

  
• What accounts for less than 1% of background radiation in the UK?

  Radiation due to nuclear waste and fallout
• What is a major natural source of background radiation?

  Radon gas from rocks and buildings

  
• How does airborne radon gas enter buildings?

  From rocks in the ground and building materials
• What radioactive element decays into radon gas?

  Uranium
• Why is radon gas particularly dangerous?

  If inhaled into the lungs in large quantities
• How can radon gas be detected?

  Using a Geiger counter
• What is the general health concern regarding radon gas levels?

  They are generally very low
• Which regions in the UK may have higher concentrations of radon gas?

  Wales and Cornwall
• What are the natural sources of background radiation?

  • Radon gas from rocks and buildings
  • Cosmic rays from space
  • Carbon-14 in biological material
  • Radioactive material in food and drink

  
• What do cosmic rays from space primarily consist of?

  Protons emitted by the sun
• What happens when cosmic rays collide with air molecules?

  They produce gamma radiation
• What is a source of cosmic rays besides the sun?

  Supernovae
• What radioactive element is found in all organic matter?

  Carbon-14
• How do living plants and animals maintain carbon-14 levels?

  By constantly replacing carbon in their systems
• What naturally occurring radioactive element is found in bananas?

  Potassium-40
• Why is the amount of radioactive material in food not a concern?

  It is minuscule
• What are the artificial sources of background radiation?

  • Nuclear medicine (X-rays, CT scans)
  • Nuclear waste
  • Nuclear fallout from weapons
  • Nuclear accidents (e.g., Chernobyl)
• Why is nuclear waste dangerous?

  For the people handling it
• What is nuclear fallout?

  Residue radioactive material from explosions
• How does nuclear fallout affect the environment?

  It increases radiation levels in tested areas
• What is a consequence of nuclear accidents?

  They contribute a large dose of radiation
• How can background radiation readings be accounted for in a lab?

  By subtracting background readings from source readings
• What is the corrected count rate?

  Count rate after subtracting background radiation
• How can the background count rate be measured?

  Using a Geiger-Müller tube with no source

  
• If a Geiger counter records 24 counts in 1 minute, what is the background count rate?

  24 counts per minute (cpm)
• How do you convert counts per minute to counts per second?

  Divide by 60
• If a source records 285 counts in 1 minute, what is the corrected count rate if background is 24 cpm?

  261 counts per minute (cpm)
• How do you convert 261 counts per minute to counts per second?

  $4.35 \text{ counts per second (cps)}$
• What methods can improve the accuracy of count rate measurements?

  • Repeating readings and taking averages
  • Taking readings over a long period of time