Scanning transmission microscopy with a 2 MeV alpha particle microbeam

Abstract

A scanning 2 MeV He+ microbeam has been used to form images of targets by scanning transmission ion microscopy. Silicon surface barrier detectors at 60 ° and 0 ° detected Rutherford scattered and transmitted α particles. Collimation of the 0 ° detector allowed bright field and dark field imaging. Image contrast was due to the target thickness dependences of multiple scattering and energy loss. Cu grids, diatoms and 0.22 μm diameter latex calibration spheres have been imaged rapidly and efficiently. Spatial resolution of 0.3 μm fwhm is demonstrated and thickness sensitivity is discussed. Comparisons with other imaging methods are made and applications are discussed. © 1987.