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Radiation count question

  1. Jul 17, 2006 #1
    For the SI measurement sieverts, are they in per seconds ? Off the internet I can find only sieverts measure as "joules per kg"

    But one of the question in my textbook ask me how much dosage a person is exposed to 3 hrs of 0.3 millisieverts
    Last edited: Jul 17, 2006
  2. jcsd
  3. Jul 17, 2006 #2
    The dose equivalence H is related with the dose:

    [tex] H = W * D[/tex]

    with W = weightfactor and D = dose in J/kg. The sievert has thus the same unit as the dose: [tex]Jkg^{-1} = 1 Sv[/tex] (when the impact of the radiation is meant)

    To answer your question: it depends on the type of radiotion how much dose a person has received, since the weightfactor for alfa-radiation = 20 (high ionisation damage) whereas beta/gamma/rontgen-radiation have a weightfactor of only 1. So this question misses some crucial information !

    --> the Sievert is a unit which is comparable when looking at the effect of the radiation. Damage by 1 Sv alfa-radiation equals 1 Sv gamma-radiation, but 1 Gy alfa-radiation does not equal 1 Gy gamma-radiation.
    Last edited: Jul 17, 2006
  4. Jul 17, 2006 #3
    the question in its entirety:

    The average radiation dose due to background radiation in Australia at ground level is 1.5 ms (milisievert) per year. Of this amount 0.3 ms is from cosmic radiation. The radiation dose due to cosmic source of a trip by plane from Sydney to Melbourne is 0.01 ms. If the trip takes 3 hrs , what radiation dose due to cosmic source does a person on the ground recieves?

  5. Jul 17, 2006 #4
    do you think cosmic radiation can be alfa-radiation ? or beta-radiation ? or gamma-radiation? (Think about the properties and particles of these types of radiation)

    This is the crucial info i meant and from this question you can determine the weightfactor for this radiation ;)
  6. Jul 17, 2006 #5
    beta radiation....cant be alfa...sweet...i'd go work on it... :smile:
  7. Jul 17, 2006 #6
    do you think the particles are electrons ? The maximum travellength of these particles is about 6 m ;)

    But it doesn't matter: W = 1 for this radiation and so the dose can be calculated for this radiation type :)
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