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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.

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I am going to close this as a "do my homework" problem which is forbidden by the FAQ. But I can point you in the right direction. There are two things to grapple with here: (1) how does the combination of (lag angle, shaft speed and separation) serve to select a particular velocity and (2) how is velocity related to wavelength. If either of these concepts is completely unclear to you probably have the makings of a good, basic conceptual question. – dmckee♦ Jul 30 '12 at 0:22

closed as too localized by dmckee♦ Jul 30 '12 at 0:23

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