ABSTRACT

The stabiliser (Figure I) applies a triangular wave form to the drift tube voltage so that the EELS zero loss peak (ZLP) is scanned back and forth across a tungsten wire. Electrons backscattered off the wire are detected by a scintillator and their signal is processed to determine if the ZLP has moved. !fit has, a correction signal is applied to the drift tube to return the ZLP to its original location. The previous design of the stabiliser placed the scintillator for the stabiliser after the wire and detected the shadow of the wire in the ZLP signal. In the new scintillator configuration, the backscattered signal of the ZLP is many times stronger than the signal from the shadow of the wire and improves the performance of the stabiliser dramatically. Because of the success of the stabiliser, 50 high loss spectra at a time could be acquired on and off dislocations and added together, without any alignment of the spectra needed.