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How do the electrons enter the bubble chamber?

  1. Jun 2, 2015 #1
    How's the electrons of the accelerated electron beam enter the bubble chamber that contains the liquid hydrogen? Wouldn't the high intensity of the electron beam cause a massive explosion and destroy the bubble chamber that has an outer wall of at least quarter inch of steel!! I think hydrogen is highly flammable and an high energy electron beam could maybe cut through steel?

    The cloud chamber's, that is the predesisor of the bubble chamber, particles are produced by a radioactive isotope that is inserted into the cloud chamber but the bubble chamber that is an offspring of the cloud chamber must somehow let the electrons into the bubble chamber to create the ionization tracks that are used to justify the existence of the subatomic particles and particle physics. Maybe someone could ask the honorable Higgs but don't give him a heart attack since he's such a nice guy and extremely funny.
    Last edited: Jun 2, 2015
  2. jcsd
  3. Jun 3, 2015 #2


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    My dissertation long ago was based on a bubble-chamber experiment, but it was with neutrinos which don't have any problem passing through the wall. :cool:

    We also saw plenty of muons from cosmic rays and the neutrino-production system, which aren't readily absorbed so a lot of them did make it through the bubble-chamber wall.

    If enough electrons (or any other kind of particle for that matter) wouldn't make it through the "normal" wall, there would have to be some kind of "entrance window" which is basically just a thinner section of wall, probably made of a different kind of material, and just wide enough to accommodate the beam.

    I've never heard of a bubble-chamber experiment involving an incoming electron beam, but I don't see any problem with one provided the intensity is low enough. Bubble chamber experiments can't easily analyze a large number of nearly simultaneous interactions, so you don't want to make the beam intensity any higher than it needs to be in order to produce a few interactions per photograph.
  4. Jun 3, 2015 #3


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    Hydrogen on its own is not flammable, it needs oxygen (or some other things) to react with.

    There might have been some experiments in early particle physics where an electron beam was shot directly into a bubble chamber, but then the intensity was low.
    Accelerator beams energetic enough to cut through things are a more recent development, and those are not shot into bubble chambers.
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