Transfocator configuration

[fredericpoitevin]

We need a way to configure the TFS (and prefocusing lenses) for any desired energy.

Resources: calc.be_lens PCDS namespace in hutch python to ensure you aren’t recreating existing functions.

Leland's notes:

The focal length of the current configuration is 4.9982 m at 9.415keV.
If you use 3x50 microns at 14.2 keV the focal length will be 4.9987 m.
However, the front 50 micron CRL is 222mm closer to the sample than the current 62.5mm crl. So we need to shorten the focal length further.
If we then make the combination 3x50 and 1x500 we get a focal length of 4.837 m. Then to bring the beam to the correct focus it should be 4.998-4.837-0.222= -0.061 m. So we should need to move the Z-stage of the transfocator -61mm from it’s current focused position (275 currently. but I remember 210?). So we should be able to find the focus in the 300 mm range of the TFS with this combination.