In this paper we describe and discuss simple, inexpensive optical experiments used to simulate x-ray and electron diffraction according to the Debye-Scherrer theory. The experiment can be used to address, at the high school level, important subjects related to fundamental quantum and solid-state physics.
REFERENCES
1.
Leybold (http://www.leybold-didactic.de/data_e/index.html) provides a diffraction tube for electrons in which the adopted polycrystal is a graphite layer (thickness ≅10 nm). A similar system is available from Tel-Atomic (http://www.telatomic.com).
2.
Simple experiments in optics about Laue diffraction can be found, for example in
Se-yuen
Mak
, “Gratings for simulation of Laue crystal diffraction
,” Phys. Teach.
32
, 539
–541
(Dec. 1994
).3.
Two-dimensional gratings are used to make “rainbow glasses.” We use holographic 2-D diffraction gratings (Rainbow Symphony, Inc.; http://www.rainbowsymphony.com).
4.
Photographs taken with a reflex digital camera (Nikon D70).
5.
For a simple, yet detailed introduction to the theory of crystal and polycrystal x-ray and electron diffraction, see, for example, E. H. Wichmann, Quantum Physics, Berkeley Physics Course, Vol. 4 (McGraw Hill, New York, 1970), and references therein.
6.
A more detailed and thorough treatment of the geometry of diffracted rays by a two-dimensional grating would lead to the result that bright spots do not lie exactly on a rectilinear grid. Actually, they fall on branches of hyperbolae given by the intersections of the Laue cones with the detection screen; see, for example, Ref. 5.
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© 2008 American Association of Physics Teachers.
2008
American Association of Physics Teachers
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