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Gamma-ray photon detection

  1. Jul 9, 2008 #1

    FNL

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    can some one give me a link or an article or his argument which Explain how the Bethe-Bloch formula is used to determine the energy of a gamma-ray photon stopped in a spark-chamber detector.

    thanks
     
  2. jcsd
  3. Jul 11, 2008 #2

    malawi_glenn

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    a gamma ray photon will undergo pair production, and it is the total amount of energy from those electrons and positrons that will be collected in an EM-calorimeter.
     
  4. Jul 12, 2008 #3

    FNL

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    yes , it will be clear
    thank you
     
  5. Jul 12, 2008 #4

    ZapperZ

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    Is this really what is occurring in such a spark chamber? From what I've understood, all it requires is that the gamma ray causes ionization in the active gas in the spark chamber. Then by looking at the energy loss of these charge ions, one can apply the Bethe-Bloch to deduce the total energy of all the created charge particle and deduce the energy of the gamma photon that cause this ionization in the first place.

    In such a low-density gas, one seldom creates pair production.

    Zz.
     
  6. Jul 12, 2008 #5

    Astronuc

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    Here's a brief article on a spark chamber.
    http://eppog.web.cern.ch/eppog/Resources/SparkChamber.html
    Another discussion - http://www.ep.ph.bham.ac.uk/index.php?page=general/outreach/SparkChamber/index

    Firstly, pair production requires gamma ray energy of at least 1.0221 MeV. PP would be possible in the boundaries and plates/electrodes.

    Secondly, I believe Compton scattering is more likely than pair prodcution, and then there is the photo-electric effect.

    Is it inferred that the gamma-rays are much greater than 1.0221 MeV?
     
  7. Jul 12, 2008 #6

    malawi_glenn

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    Yes ZapperZ, that is correct of you, forgot to read the last word 'spark chamber' properly :)
     
  8. Jul 16, 2008 #7

    FNL

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    Thanks
     
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