Intelligent interface for a microprocessor controlled scanning transmission electron microscope with x‐ray imaging

Abstract

AbstractAn intelligent interface has been designed to perform synchronous digital image acquistion and scan generation (SDIASG interface) for a microprocessor controlled Scanning Transmission Electron Microscope (S(T)EM) with x‐ray imaging. The SDIASG interface connects an LSI‐11/2 microprocessor to a Philips EM400 electron microscope. The LSI‐11/2 microprocessor is part of a DeAnza VC5000 digital image display system. A system using the SDIASG interface is described. The system takes advantage of the SDIASG interface and a DeAnza VC5000 digital image display system to realize new capabilities that optimize conditions for x‐ray mapping.A low characteristic x‐ray count rate is generated by the ultrathin specimens from which high resolution x‐ray maps can be obtained (Shuman et al, 1976; Somlyo and Shuman, 1982). This low count rate necessitates a long image accumulation time, which in turn makes drift correction essential for maintaining spatial resolution. The new capabilities of the system described here consist of real‐time display and summation of consecutive image and x‐ray maps, and automatic return to a high speed imaging mode between consecutive x‐ray map passes. The new capabilities combine to allow frequent correction for specimen drift between consecutive x‐ray mapping passes while still permitting a long total accumulation time for the x‐ray maps.