School of Physics Lecture Demonstration Manual

Na-10 Bragg Diffraction

Published: Friday 17 March 2006 - Updated: Thursday 31 March 2011


To demonstrate Diffraction in a NaCl crystal with X rays.



Click on pictures to enlarge.

Bragg Diffraction Pic


The X ray apparatus produces X rays with an energy of 20 or 30KeV. The collimated beam is directed to a Na Cl crystal where Bragg diffraction produces the strong peaks at the Bragg angles. A ratemeter accepts the output from a geiger tube located inside the X ray apparatus. It has an audible output as well as a meter reading. A full plot of the intensity versus angle gives the expected background spectrum and the cutoff wavelength may also be demonstrated.

 NB: This demonstration may not be available if the experiment is in student use in the Part 1 laboratory.

Safety notes

Electrical safety 

Radiation safety 


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