Understanding X- rays

• Irradiate the sample surface, hitting the core electrons ( e^- ) of the atoms.

• The X-Rays penetrate the sample to a depth on the order of a micrometer.

• Useful e^- signal is obtained only from a depth of around 10 to 100 Å on the surface.

• The X-Ray source produces photons with certain energies:

• MgKα photon with an energy of 1253.6 eV

• AlKα photon with an energy of 1486.6 eV

• Normally, the sample will be radiated with photons of a single energy ( MgKα or AlKα ). This is known as a monoenergetic X-Ray beam.