Muon asymmetry fitting suggestions

[Tom-Willemsen]

Suggestions from JL following testing of #227:

• On failed fits, return NaN as fit parameters

  • Requires some work to 'chase through' various consumers who will be upset by NaNs, e.g. lmfit at outer level will need nan_policy="omit"

• Want to expose a "figure of merit" which is (asymmetry)^2 * (count rate) from MuonAsymmetryReducer

  • Should be relatively easy to expose this from MuonAsymmetryReducer
  • If the asymmetry fit fails on a low stats run, the asymmetry shouldn't exceed 1 anyway so a good substitute is just to put Figure of Merit=rate in this case. Assuming other scan points have a large flux and fit successfully, it'll be close to the baseline for the outer peak fit.
  • For the two-oscillation function there will be figure_of_merit_0 and figure_of_merit_1 derived from A_0 and A_1 respectively. I'll want to choose to plot/optimise one of these.

• Expose r_squared from MuonAsymmetryReducer.

• Give more decimal places on the soft signals that hold fitting results

• Once Argus: configuration based on double/single pulse mode IBEX#8809 is done, read $t_0$ and $t_{good}$ PVs and use these to set the start of the data rebinning range (this is an adjustment in the inst scripts side, not in ibex_bluesky_core).

  • Adjust all DAE time coordinates by subtracting $t_0$, then set rebinning to start at $t_{good}$