Practical

• Investigate the Penetration of Radiation

  1. Detect ionising radiation with a Geiger-Müller detector

  2. Geiger-Müller detector gives a count rate - the number of radioactive particles reaching it per second

  3. Set up equipment so counter records high count rate when nothing is placed between source and detector

  4. Remove source to measure background count

  5. Replace source and measure count rate with no material present

  6. Insert different materials between source and detector and record count rate

  7. Repeat experiment with different sources
• If the count rate remains about the same when the material is inserted, then the radiation can penetrate the material
• If the count rate drops by a large amount, then the radiation is being absorbed and blocked by the material
• If the count rate drops to zero after the background count is subtracted, the radiation is being completely absorbed
• Radioactive sources can be dangerous if you don't use them properly
• Radioactive sources should be kept in a lead-lined box when not in use
• Radioactive sources should only be picked up using long-handled tongs or forceps
• Take care not to point radioactive sources at anyone, and keep a safe distance from them
• You can also investigate this using a computerised radiation simulator