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Proton beam questions

  1. Dec 19, 2013 #1
    Hello everybody.

    I am going to propose an experiment with a proton beam at CERN for a contest. This contest.
    Also this are the specifications of the beam and available devices for detecting the particles.

    However I have several questions about the beam working.

    1.-At "Target" is says: "There are different target heads available, allowing different electron components of the beam".
    Does it mean that the beam will always shoot electrons and not protons?, does it shoot electrons and protons?, depending on the target head, can it shoot only protons?

    2.-About the Cherenkov counter
    What I understood of the Cherenkov counters is that they are like particle filters, am I right?, and if so, how can I know what kind of particles specifically can it filter?

    The Collimator can filter particles by their momentum and angle, I got that, but then can it be used to filter different kinds of particles?, I think it can but I am not sure, because as the particles are generated it may be possible to know which kinds of particles will have which values of momentum and inclination. Is that right?

    4.-What does it mean to "flag" a particle?, as it says that the Halo counter can do

    Thanks a lot for your answers
    Last edited: Dec 19, 2013
  2. jcsd
  3. Dec 19, 2013 #2


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    Staff: Mentor

    This does not look like quantum physics. I moved the thread to our particle physics forum - this is not a final decision, the thread could get moved again. The url will stay the same, and you can always find the thread via your control panel or a search for your own posts.

    Concerning your questions:
    1. Collisions in the target will always produce all particles mentioned there. The fraction of electrons in the extracted beam depends on the target. Heavy elements tend to produce more electrons and positrons due to Bremsstrahlung and pair production.

    2. They do not filter, they just help to identify the particles. You still get all particles, but in the data analysis you can tell which particle was which type (not with 100% accuracy, however). They detect the velocity of particles. Together with the momentum (which you can set via the magnets), this allows an estimate of the mass of the particles. Electrons are very light, pions and muons are much heavier, kaons are a bit heavier than pions and protons are the heaviest particles you'll get. The antiparticles always have the same mass as the particles.
    Muons can be identified with the muon filter there, separating pions and kaons is a bit tricky, for the other particles the separation should be reasonable (but I don't know how good the two detectors are).

    That is not possible. The collisions are random processes.

    Pions will be the most frequent particles, probably followed by kaons and protons, and muons should be quite rare. Electrons will be somewhere in between, depending on the target material.

    4. The recorded data gets an entry "halo counter saw a particle at the same time" if that happens.
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