Precision velocimetry in a thermal atomic beam by stimulated optical Compton scattering

The high atomic densities found in atoms that were released from a magneto-optical trap (MOT) to the lower density of atoms in a thermal beam were reported. Transverse velocimetry was done by measuring the spatial distribution of the atoms at the end of the beam line. Good velocity resolution required a long beam line and narrow beam defining slits to maintain the necessary spatial resolution. The results of the experiments gave a compact, portable, self-calibrated velocimeter for cold atoms identical to Compton effects. Measured absorption or gain of the light beams with sufficient frequency resolution allowed determination of a chosen component of the initial atomic velocity to accuracy of the order of the recoil velocity.