A method by which one can determine the structure,
atomic arrangement, purity, and identity of unknown crystaline substances.
An X-ray Diffractometer consists of the following components:
1. x-ray tube: consists of a metal casing, a tungsten filament, copper plate, cooling devices, and up to 4 focal points for the x-ray beam.
2. target: stand upon which your unknown (or known) substance is placed
3. detector: like a camera for x rays. It records the patterns of the x-ray "diffraction" or reflections off the substance's surface.
4. Lead casing: umm, keeps out radiation, duh!
The
tungsten fillament is supplied with a current. When the filament is
excited it gives off heat. This heat excites the copper target into giving off
electrons (x rays). A cooling device is present so that the
copper target does not melt. These x-rays are in turn
projected through the
focus point of the x-ray tube towards the studied substance. The atoms
absorb x-rays and
emit them in all directions.
Interference of these waves cancel each other out, except at the diffraction angle. The
waves at those angles are read by the detector. The x-ray tube is then rotated around the subject so that a reading may be taken from multiple
angles (denoted as 2θ). The readings from the reciever are then (finally) transposed into a readable
graph by PC software (ie JADE).