Electron micro-densitometry during in-situ TEM investigations

Abstract

An electron detector with small detection area for use in the final image plane of a transmission electron microscope has been commercially offered by TEM manufacturers (1). However, little has been reported about the application of such a device. In this report, the construction principle and the operation of a novel microdensitometry device is described which combines precision image point selection with versatility, high sensitivity, ease of operation, and comparatively low cost.The electron microdensitometer system consists of a transparent phosphor screen onto which the electron image is projected, a small “channeltron” electron multiplier (supplied by Galileo/Bendix) underneath, and a closed-circuit TV system (Fig.l). The screen has an effective diameter of 45 mm and contains a 2 mm concentric hole which allows a small beam of electrons to pass unobstructed to the electron multiplier. The multiplier consists of a 3 mm O.D. tube in custom L-shaped configuration and is mounted such that its collector is located outside the screen area to minimize obstruction of the image viewed on the TV monitor.