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Electrons in bubble chamber photographs?

  1. Jun 4, 2012 #1
    If bubble chamber tracks are formed by charged particles leaving a trail of ions as they pass through, by knocking electrons out of atoms, then why aren't there spirals of electrons along the whole track?

    Also, are the straight lines in bubble chamber photographs actually curves of a very very large radius?
     
  2. jcsd
  3. Jun 4, 2012 #2

    mfb

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    Low-energetic particles have a very small curve radius - too small to get resolved.
    If there is a magnetic field, they should be curves.
     
  4. Jun 4, 2012 #3
    So the straight lines are curves of very great momentum?
     
  5. Jun 4, 2012 #4

    mfb

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    I don't see a way to get a (theoretical) straight line. Just curves with really large radius.
    Simple example: Muons from cosmic radiation usually have an energy larger than ~10GeV. With a magnetic field of 1T, this results in a radius of ~30m or more.
     
  6. Jun 4, 2012 #5
    Thank you very much!!
     
  7. Jun 4, 2012 #6

    jtbell

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    These "knock-on" electrons need to gain a fairly large amount of energy in order to be visible as separate tracks. It does happen sometimes.

    http://teachers.web.cern.ch/teachers/archiv/HST2005/bubble_chambers/BCwebsite/gallery/gal2_12.htm

    They're also called "delta rays." I saw plenty of these while working on a bubble chamber experiment as a graduate student long ago.
     
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