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The principle of the ECD of a GC (and possible balloon modification)

  1. Aug 4, 2011 #1
    I got this question from a british friend, who has worked with GCs before. I was not sure if to post it here or in the Nuclear Physics section, but I hope here is the right place to ask.

    As he is also involved with high altitude balloons, he once thought of a device similar to the Electron Capture Detector of a GC on the balloon, which would be able to measure the amount of halogenated compounds in the high atmosphere. However, it is understandable that the classic ECD cannot be used due to it containing Ni-63.

    The only other method to obtain free electrons for the electron stream (and also a safe method to do so) seems to me to use the photoelectric effect by having a UV lamp illuminating a Zinc plate. The question now is the following: I think that the detector relies on that the molecules capture the electrons from the flow and that a certain energy is needed for this. WolframAlpha gives me that the energy of a beta ray emitted by Ni-63 is about 67 keV. If the electrons created by the photoelectric effect would have to be accellerated electrically to have the same energy, this would require 67 kV.

    Is it required that the electrons have this high energy or is a lower energy sufficient? Despite that my friend had worked with GCs he stated that he does not know the details anymore and because I also don't know that much about it, I decided to try and ask here.

  2. jcsd
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