[3dem] electron diffraction

[Philip Köck]

Hi everybody,

I'm looking for a simple estimation that I can't find in any textbook I've looked in, nor on the internet.
I wonder if anybody can help me.

If I put a diffraction grating with spacing 1 Angstrom into the specimen holder and record an image of it.
At what distance from the optical axis will the corresponding diffraction spot (for 1 Angstrom spacing)
appear in the back focal plane of the objective lens.

Assume a TEM with 200 kV and a twin lens, one that's typically used for protein structure determination.

Thanks,

Philip