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Davisson-Germer Experiment [20 pts]

In a Davisson-Germer experiment, a beam of neutrons (mass ), each with kinetic energy , travels toward a crystal of spacing d=3Å between atoms along its surface. A detector of width counts the rate of the total number of neutrons which enter it. The detector sits at a distance of from the target crystal and detects neutrons scattered at angles near from the surface. (See Figure 2.)

Compute the spacing between the expected interference maxima in terms of m, d, E, and h. By observing the changes in the rate of the arrival of neutrons as the position of the detector is varied, will the experimentalist be able to detect the interference pattern of the scattered neutrons?

Hint: If you have an expression of the form , differentiating both sides of the expression will allow you to determine .

  
Figure 2: Davisson-Germer Apparatus




Prof. Tomas Alberto Arias
Thu Mar 7 15:22:31 EST 1996