International
Tables for Crystallography Volume B Reciprocal space Edited by U. Shmueli © International Union of Crystallography 2006 
International Tables for Crystallography (2006). Vol. B. ch. 2.5, p. 279


Figure 2.5.2.1
The variation with accelerating voltage of electrons of (a) the wavelength, λ and (b) the quantity which is proportional to the interaction constant σ [equation (2.5.2.14)]. The limit is the Compton wavelength (after Fujiwara, 1961). 