CHARGE-COUPLED-DEVICE BASED TIME-OF-FLIGHT CHARGED-PARTICLE ANALYZER

The time-of-flight technique is well suited for the analysis of electr ons photoemitted from a surface by a pulsed laser. In this paper, a no vel design for a time-of-flight charged particle analyzer is presented which incorporates a charge-coupled device (CCD) for the direct detec tion of electrons photoemitted by an ultrashort laser. After traveling through a field-free drift region, the electrons are accelerated, foc used, and deflected onto a CCD. The positions at which the electrons s trike the CCD determine their flight times through the drift region. T he use of this analyzer is demonstrated by detecting electrons emitted from a Cu(111) surface by two-photon photoemission. A computer simula tion of the electron trajectories reveals that degradation in resoluti on and throughput at higher energies can be traced to the chromatic ab errations of the acceleration region just past the drift region.