feat/bug: Update SST1 i0 correction

[pdudenas]

Some of the headerdict keys used in the correction step for the SST1 loadSingleImage function are from ALS 11.0.1.2 and don't work for SST1 data. This is part of a larger issue on normalization. To do this properly we need to read in the sample Au mesh current and a calibration scan under the same conditions.

[pbeaucage]

This would be really great! I think the place I would start with it would be in the Databroker loader since we have (theoretically) infinite access there to any scan (so you can just specify a scan number for the calibration). The Au mesh is pretty easy in DB as well.

[EliotGann]

In the future this will be much easier with a preprocessor for diode calibrations... working on that now on the acquisition side. then there will be a new stream just like the dark stream now, which just includes the calibration scan

[pbeaucage]

I0 correction, albeit without a i0 / diode correction term, is implemented in commit 45cdfe9 along with support for getting monitor values at all points.

[pbeaucage]

OK, so we have i0 now in the form of the mesh reading. The thing we really need, though, at least I think so in a mildly sleep deprived state, is to multiply the measured mesh(E,pol,slitconfig) by the ratio (diode/mesh)(E,pol,slitconfig) for an open beam diode scan so as to get the true i0.

What is the best way to get that function in? There are several good options:

• have the user do the matching of slitconfig and provide a scan number in E/pol space. Our loader can munge that scan into (diode/mesh)(E) and make i0 from that ratio
• have a preparation process generate a LUT of (diode/mesh)(E,pol) as a h5 or nc file and have the user provide (or loader grab from somewhere) the appropriate LUT.
• something else entirely.

@pdudenas @EliotGann