Using coherent illumination to extend HRTEM resolution: Why we need a FEG-TEM for HREM

Conference · Sun Nov 01 04:00:00 EST 1992

OSTI ID:10134093

O`Keefe, M A

Resolution of a high-resolution transmission electron microscope (HRTEM) has traditionally been defined in terms of its Scherzer resolution limit at optimum defocus. However, even beyond the Scherzer limit, spatial frequencies can be transferred from the specimen to the image, out to the so-called information limit of the electron microscope. The information limit of the HRTEM is determined by the degree of energy spread in the electron beam used to illuminate the sample. Since a HRTEM equipped with a field-emission gun (FEG) will produce an electron beam of high coherence with little energy spread, it can achieve an improved information-limit, and can thus be used to produce through-focus series of images containing information well beyond its nominal (Scherzer) resolution limit. Suitable computer processing of such series of images can produce composite images at resolutions approaching the microscope information limit. For such a FEG-TEM, combined with suitable computer image processing, resolution can approach 1{Angstrom}. 12 refs., 9 figs.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 10134093
• Report Number(s): LBL--33157; CONF-9210311--2; ON: DE93007724
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400101
ACTIVATION, NUCLEAR REACTION, RADIOMETRIC, AND RADIOCHEMICAL PROCEDURES
BEAM OPTICS
COHERENT RADIATION
ELECTRON BEAMS
ELECTRON MICROSCOPY
FIELD EMISSION
FOCUSING
IMAGE PROCESSING
RESOLUTION
TRANSMISSION ELECTRON MICROSCOPY