Premium
The effect of variations in objective focal length on electron microscope performance
Author(s) -
Lovell D. J.,
Chapman S. K.
Publication year - 1975
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1975.tb04060.x
Subject(s) - focal length , magnification , optics , resolution (logic) , electron microscope , materials science , microscope , transmission electron microscopy , physics , lens (geology) , artificial intelligence , computer science
SUMMARY Standard specimens were examined in a transmission electron microscope with a top entry stage. Using a range of objective focal lengths, measurements of contrast, resolution and magnification range were made. Focal lengths up to 14 mm were examined. The contrast was found to increase with increasing focal length, being twelve and a half times greater at 14 mm focal length than at the normal high resolution mode of 2 mm focal length. Resolution, determined by the fresnel fringe method decreased from 0·3 nm to 3·5 nm. The photographic image magnification was reduced from × 1000– × 500,000 at 2 mm focal length to ×100‐× 50,000 at 14 mm focal length.