X-rays, are a form of high energy electromagnetic radiation. Through various other experiments, we have learned that electromagnetic radiation can be analyzed by diffraction.
 

( If the pitch of the diffraction grating used for this analysis is known then the wavelength of the e-m radiation in question can be determined. )
   Sir William Henry Bragg

Objective: To analyze the characteristic wavelengths of x-rays emitted from a copper anode by diffraction while using single crystals as the "grating".

The production of X-rays is extremely simple.  Electrons bombard a metal target anode at high energy (>20 keV), the target anode is oriented at about 45o to the electron beam, and X-rays are emitted about 90o to the electron beam.

The device that is familiar to us for detecting X-rays is called the Geiger-Muller tube.  The G-M tube essentially counts the number of events in which X-rays enter the detection device.