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Where could I buy electron guns?

  1. Nov 29, 2009 #1
    Hi everyone.

    I've searched the internet, but has great difficulty finding places to buy electron guns. I would appreciate any feedback!

    Kind regards,
  2. jcsd
  3. Nov 29, 2009 #2


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    Staff: Mentor

    Welcom to PF.

    You'll need to be a little more specific about you are looking for because any decent electronics store still sells TVs that use an electron gun.
  4. Nov 29, 2009 #3
    I want an electron gun that could neutralize an ion beam of about 3mA. The only proper site I found was this one: http://www.kimballphysics.com/electron_guns/egun_prod.htm
  5. Nov 29, 2009 #4


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    Staff Emeritus
    Science Advisor

    Normally, one would not use an electron gun to neutralize on ion beam. One uses a neutralizer that recombines the electrons from the ion source with the ions. This is the principle behind a neutral beam injector.

    Ions will only remain ions in a vacuum, and on earth, that would in a vacuum chamber containing the ion source, which would mean that the electrons from those ions are somewhere nearby (usually).
  6. Nov 29, 2009 #5
    Yes, this is my idea. I wish to neutralise the ion beam coming out of an ion thruster. Could you please give me a little more light on the subject Astronuc?
  7. Nov 29, 2009 #6
    One source of neutral ions is to accelerate negative ions, and then strip the extra electron off to produce a neutral ion. The Spallation Neutron Source (SNS) in Tennessee accelerates negative hydrogen ions (one proton with two bound electrons) up to 1000 MeV, and then strips the extra electron off with either a laser or a thin foil. The neutral ion is a hydrogen atom, with only one electron.
    Bob S
  8. Nov 29, 2009 #7


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    Staff Emeritus
    Science Advisor

    Ah - ok. Some use trailing electrodes, others some kind of injector.

    Here's one using an injector.
    Characterization of an Ion Thruster Neutralizer
    http://gltrs.grc.nasa.gov/reports/2005/TM-2005-213883.pdf [Broken]

    Also try this invention - http://www.freepatentsonline.com/4838021.pdf
    Last edited by a moderator: May 4, 2017
  9. Nov 30, 2009 #8
    Thanks alot. Ive looked at the following general purpose
    thermionic emitters: http://www.kimballphysics.com/cathode/catalog_PDF/tantalum cathodes.pdf.

    They look good to me, am I correct? One of them has the same current as my ion motor, 3mA, so it would then be able to neutralise the beam? Thanks again!
    Last edited by a moderator: May 4, 2017
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