Use of Digital Voltmeter for Selected Area Diffraction Calibration
Gene R. Grieger · Proceedings annual meeting Electron Microscopy Society of America · 1971
In the interpretation of selected area electron diffraction patterns, the crystal interplanar spacing value d is generally obtained from the formula (1) where D is the measured diameter of the diffraction photograph and F is an instrument factor. The value of F is defined as (2) where λ is the deBroglie wavelength of the high voltage electron and Le is the effective length of the diffraction camera. The error is d then is (3) The error in λ for most modern instruments is quite small, 0.01% or less. The diameter of the ring D can, in general, be read to 0.1 mm which for most patterns is about 0.1%-0.2%. The major source of error in disdue to error in F in general and Le in particular.