The possibility of placing the specimen in a gaseous medium in the environmental SEM (ESEM) has created novel ways for detection of signals from the beam-specimen interactions. It was originally reported by Oanilatos that the ionization produced by certain signals inside the conditioning medium can be used to produce images. The aim of this report is to demonstrate some of the improvements on the system that have occurred thereafter.Two straight thin wires are aligned horizontally along a direction normal to the direction of the two scintillator backscattered electron (BSE) detectors reported elsewhere. The free end tips of the wires are about 5 mm apart halfway between the specimen and the pressure limiting aperture (specimen distance = 1.5 mm). The other end of each wire makes contact with the input of a separate preamplifier, two of which are built inside a shielding aluminum stub. With such a design, interference noise from the input cables is avoided.
