Auger-Photoelectron Coincidence Measurements in Copper

We demonstrate the feasibility of Auger-photoelectron coincidence spectroscopy (APECS) and use this technique to study the Cu $L_{23}{M}_{45}{M}_{45}$ Auger transitions. With APECS the Auger lines can be identified unambiguously and the Coster-Kronig-preceded Auger lines separated from the main $L_3{M}_{45}{M}_{45}$ lines. The background due to scattered electrons is strongly reduced relative to that in conventional Auger or photoelectron spectroscopy. Some other interesting experiments that can be done with this technique are discussed.