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Homework Help: Neutron velocity selector and rotational speed of shaft

  1. Jul 29, 2012 #1
    1. The problem statement, all variables and given/known data

    Suppose that there is a beam of neutrons with a range of wavelengths. One intends to produce neutrons of single wavelength by the use of neutron mechanical velocity selector.

    The question is, if the slot in the disk B (second disk) of the selector lags the slot in the disk A by 10 degrees, and two disks are separated by 0.5m, how do you calculate how fast should the shaft that connects the disks rotate? (target wavelength as 1 angstrom as an example.)

    I am just getting lost, so I ask for your help.

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jul 29, 2012 #2


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    If you know the wavelength of the neutron, then you should be able to find the speed of the neutron. With that speed, how much time would it take to travel the distance from one slit to the other? How would you use this time to find the angular speed of the disks?
  4. Jul 29, 2012 #3
    Thanks. I got it.
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