TOFLAS-3000 is composed of ionization source, neutralization room (converting ions to atoms), micro-channel plate (MCP) detector and main analysis vacuum chamber.
The ions generated in the ionization source are accelerated and chopped into a pulsed beam. The pulsed beam is neutralized in the neutralization room and transformed into neutral (atom) beam.
The atom beam hitting the sample surface is scattered all the directions. Only backward-scattered atoms are detected by MCP detector, the energy and frequency of detected atoms are measured by time of flight (TOF) analysis.

Elemental and structural analysis of a crystal surface can be made by the time of flight techniques, because an energy and density of a scattered atom depends on the mass and the density of the target atom in/on the crystal surface.
When the atom in the second and the third atomic layer is covered by the shadow corn due to the first atomic layer, shown in the left (A), the atoms only in the first atomic layer can be detected. In case of (B), the first and the second layer’s atoms are detected. Thus, the crystal structure of the surface can be analyzed by examining the incident angle dependence of the scattered intensity at desired flight time.