XRD Theory
The Scanning Cycle
X-rays are generated when a stream of accelerated electrons strike an atom. The hot filament is the source of electrons and anode, made of copper, the atom. A voltage potential of 20kV and a tube current .3 to .5mA generates the electron stream. Intense radiation of discrete wavelengths, due to the copper anode, is emitted from the two windows. The wavelength we use is 1.537395 x 10 -8cm. The double crystal system is used as a filter and is called the monochromating crystal. This crystal is carefully prepared and permanently mounted to reflect only the wavelength above. The crystal sample is mounted on the goniometer and rotated about an axis through its surface until the atomic planes are in a position to satisfy the Bragg relation for the incident monochromatic wavelength. This condition is determined by a maximum reading on the PEAKING meter.