Skip to main content
. Author manuscript; available in PMC: 2012 Dec 1.
Published in final edited form as: Ultramicroscopy. 2011 Oct 4;111(12):1688–1695. doi: 10.1016/j.ultramic.2011.09.015

Figure 3.

Figure 3

Images (and their Fourier transforms) of a graphitic particle that were recorded with a hybrid dsb/ssb aperture positioned (A) with the straight edge close to the unscattered electron beam and (B) with the device pulled back such the straight edge is located approximately half way between the unscattered beam and the diffraction ring from the 3.4A spacing of graphite. The pixel size of the CCD camera is 24 µm, and the image magnification at the camera is 220,000. The image recorded with the hybrid aperture (panel A) shows increased contrast relative to the image recorded with the aperture removed a considerable distance from the center of the electron diffraction pattern (panel B). The Fourier transform (panel C) of the image in panel A, recorded with the device centered in the intended way, demonstrates that signal is well preserved at a resolution of 0.34 nm when using the ssb aperture. The Fourier transform (panel D) of the image in panel B, which was recorded with the device shifted well off center, nevertheless demonstrates that there still is a small amount of charging. Charging is evidenced by the bright line in the FFT at the edge of the aperture and by the distorted shape of the first Thon ring.