goldtool

Interactive tool for obtaining the shape of the Fermi edge from data such as a gold reference spectrum.

goldtool can be started with erlab.interactive.goldtool():

import erlab.interactive as eri

eri.goldtool(data)

It can also be opened from the right-click context menu of any image plot in ImageTool.

Use the %goldtool magic (see Notebook shortcuts) to launch it directly from IPython.

When goldtool is opened from an ImageTool in the manager, it remembers the selected spectrum or slice that opened it. If that ImageTool changes, the manager can mark the tool and its corrected ImageTool window as Stale. Enable Refit after update when you want the edge fit to rerun automatically after compatible updates.

Fermi edge fit controls

The ROI defines the detector-coordinate range and the outer energy range used for the fit.

  • T (K) sets the sample temperature. Fix T controls whether the parameter is fixed in the fitting process.

  • Resolution sets the initial energy-resolution FWHM in electronvolts.

  • Step edge uses a Gaussian-broadened step instead of the Fermi-Dirac model. It disables Fix T.

  • Adaptive estimates a separate energy range for each EDC inside the outer ROI range. An EDC uses the complete outer range if no valid falling edge is found.

  • Bin x and Bin y average adjacent detector and energy points before the fit.

  • Linear includes a linear background above the Fermi level.

  • Method selects the lmfit minimizer. Scale cov controls covariance scaling.

  • # CPU sets the number of parallel workers.

  • Go starts the fits.

The Polynomial and Spline tabs control the model fitted to the edge centers:

  • Residuals shows the difference between the fitted model and edge centers.

  • Corrected shows the corrected reference data.

  • Shift coords lets the corrected output change its energy coordinate and length so that it retains the complete shifted range.

  • Open corrected in ImageTool opens the corrected reference data.

  • Open edge in ImageTool evaluates the selected model on the input detector coordinates and opens the resulting edge positions. In Manager, this output can be used as the shift source for another compatible ImageTool.

See Fermi edge correction for more information on using the Fermi edge fit controls and the corrected output.