22. Investigation of the variation of intensity of gamma radiation with distance

  • 00:30 Why is there a background count?
  • gamma source (e.g. 185 kBq (5 μCi) Cobalt 60 ‘closed’ source)

  • source holder or retort stand, boss and clamp

  • counter with integral power supply for GM tube

  • geiger muller tube suitable for gamma detection

  • metre ruler

  • stopclock

Hazard Risk Control measure

Radioactive source

The radioactive source may cause cancer

See CLEAPSS Guide L93 for guidance