Scanning electron microscope electron detector with a radial type discrete dynode electron multiplier

A discrete dynode electron multiplier with radial flux of electrons was built and tested in the range of low-voltage scanning electron microscopy as a backscattered electron detector of topographic contrast. The multiplier collects backscattered electron emitted in a specific range of take-off angles and over the whole azimuth angular range enabling large solid collection angle. Multipliers with different dynode shapes were studied theoretically with the use of the software for particle optics and three assemblies were built and tested experimentally. The gain estimation, assessment of the type of detected electrons (secondary electron or backscattered electron), imaging the spatial collection efficiency and signal-to-noise measurements were performed.