It seems as though the equation here ($d\sinθ=1.22\lambda$) is more or less the same as the equation for diffraction gratings ($d\sinθ=n\lambda$). However, in the equation for the gratings, d is the grating spacing, not the thickness of one of the gratings, which is how I'm assuming the nuclei would act in this set up (as the gratings). So how is it that the electron diffraction equation can tell us the diameter/radius of the nucleus, and not the distance between nuclei i.e. the grating spacing?
Also if anyone know why we use 1.22 that'd be great, I know it's something to do with the Rayleigh criterion but haven't been able to find a suitable explanation for it in this context.