Ch 5.3 Radiation Mesurement

Geiger Counter

A Geiger counter is a common instrument that

  • detects alpha particles, beta particles and gamma rays

  • uses ions produced by radiation to create an electrical current

Units for Measuring Radiation

  • curie (Ci) - the number of disintegrations that occurs in 1 s for 1g of radium, equal to 3.7 × 10310^3 disintegrations/s

  • becquerel (Bq) - the SI unit of radiation activity which is 1 disintegrations/s

  • rad (radiation absorbed dose) - measures the amount of radiation absorbed by a gram of material such as body tissue

Measuring Radiation Damage

  • to determine the equivalent does or rem dose,

    • the absorbed dose (rad) is multiplied by a factor that adjusts for biological damage cause by a particular form of radiation

  • Biological damage (rem) - absorbed dose (rad) x factor

Radiation Measurement

  • often the measurement for an equivalent dose will be in millirems (mrem)

  • 1 rem = 1000 mrem

  • the SI unit is the sievert (Sv)

  • 1 Sv = 100 rem

Dosimeters Measure Radiation Exposure

  • Dosimeters detect the amount of radiation exposure from x-rays, gamma rays and beta particles