Shadowing pattern imaging with high-energy secondary electrons induced by fast ions

High-quality images of the ion-beam shadowing effect in single crystals have been constructed with keV secondary electrons induced by 60-MeV oxygen ions. Under a high count rate (∼104 counts/s) of the electron yield, the time needed to measure the electron yield for about 3000 tilt angles, from which the shadowing pattern for a 1deg x 1deg angular space (for two independent tilts) was obtained, was 40-60 min when accumulating the electron yield up to 5000-10000 counts per tilt angle. This practical method for visualizing the crystal lattice is suitable for characterization of crystalline materials. (author)