This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.
Similar to the effect of chromatic aberration, spatial resolution of EFTEM mapping is also affected by spherical aberration, given by,
ΔdS = 2CSβ3 -------------- [1941a]
For instance, assuming the spherical aberration constant is 0.7 mm, collection semi-angle 15 mrad, the ΔdS is ~3.8 nm.
For thick specimens (with multiple scattering) the calculation in Equation 1941a predicts the CS-effect on the spatial resolution well, while for a thin specimen the characteristic inelastic scattering angle is much smaller, given by,
β -- The collection angle,
CS -- The spherical aberration.
θe = γΔE/2E0 ----------------------- [1941b]
γ -- The relativistic correction
factor (=(E0+mec2)/(E0+2mec2), e.g. =0.61 for 300 kV).
θe is normally ≤0.6 mrad. Substituting θe for β in Equation 1941a, we can know that ΔdS is normally negligible for most microscope configurations.