Radioactive Material

Useful rules of thumb, frequently asked questions, hints and tips related to radioactive materials (half life, dose rate, exposure potential etc).

  • Formula for calculating dose rates from gamma emitting radioactive materials

    Published: Mar 01, 2024

    Source: Ionactive Radiation Protection Resource (Mark Ramsay, RPA)

      Tags:
    • Gamma emitter
    • Dose Rate
    • Formula
    • Radioactivity
    • D=ME/6r2
    • Gamma rays
    • Gray (Gy)
    • Sieverts (Sv)
    • MeV
    • Mass energy attenuation coefficient
    • Linear attenuation Coefficient
    • Air absorption factor
    • Tissue absorption factor
    • Cobalt 60
    • Co-60
    • Caesium-137
    • Cs-137
    • Iridium-192
    • Ir-192
    • Low energy photons

    A rule of thumb updated for 2024! This article considers the following expression D=ME/6r2 which has turned up in text books and training courses, but there appears to be no direct reference to when it was created and by whom. We start by using the expression with Cs-137 and see how the results compare with other resources available for calculating dose rates for chosen radionuclides with given activity and distance. We then hand over to Dr Chris Robbins of Grallator who is a maths, physics and nuclear physics whizz who derives this expression from first principles, outlining the good, the not so good and how it can be improved.

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  • The 10 half-life rule of thumb for radioactive materials

    Published: Sep 29, 2021

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  • Distance travelled by Beta Particles in air and other materials

    Published: Sep 29, 2021

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  • Distance travelled by Alpha Particles in air and other materials

    Published: Sep 29, 2021

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Two things are infinite: the universe and human stupidity; and I'm not sure about the universe

– Albert Einstein -