Diameter of the beam between which 68% of the electrons fall. For Gaussian beam shapes this corresponds to the 2
-value of the intensity distribution of the beam. Measurement can be carried out by scanning a beam across a sufficiently sharp edge and recording the transmitted electrons.
Source:
PAC, 1983, 55, 2023
(Nomenclature, symbols and units recommended for in situ microanalysis (Provisional))
on page 2027
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
doi:10.1351/goldbook.
