Add reader for accurion data

[quentintanguy]

Provides a way to import data from Accurion EP4 ellipsometer, similar to woollam, nexus and spetraray.

[domna]

Thank you for the new code. Could you provide an example file which you could contribute for a test function for your reader?

[quentintanguy]

Thank you for the new code. Could you provide an example file which you could contribute for a test function for your reader?

Attached is a zipped raw file directly saved from the Accurion EP4 tool.
Si3N4_on_4inBF33_W02_20240903-150451.ds.zip

It's supposed to be ~874nm of non-stoichiometric Si3N4 on Borofloat33. The measurement was done with a scotch taped on the backside of the BF33 wafer to scatter as much as possible the unwanted reflections from the backside. This is because transparent substrates are always harder to measure. Btw, I wonder if there is a way to circumvent that issue by tweaking the TMM or including a roughness parameter to fit in the model. Just an idea for another thread maybe...

You can load the file that way:

import pandas as pd
idx = pd.IndexSlice
data = read_accurion_psi_delta(psi_delta_path, wrap=True).loc[idx[:, 400:1000], :] # for multi-angle fit

And the BF33 is found as (in case you want to try the fit):

rii_db = elli.db.RII()
BF33 = rii_db.get_mat(book="SCHOTT-multipurpose", page="BOROFLOAT33")

[domna]

Thank you @quentintanguy. Could you add your data files and a test to your PR? That way we know that the reader works and see if something breaks them in the future.

You can basically copy this reader test for woollam data: https://github.com/PyEllips/pyElli/blob/master/tests/test_wollam.py
The data files would go to tests/test_accurion.

Other than that linting is failing. We use ruff to auto format our code. You can simply do this by pip install ruff==0.4.8 and then running ruff format on the code. This should do the formatting automatically for you. Could you do this as well?

[domna]

Thank you for the useful additions. I left some comments for some changes/additions necessary prior to merging. If anything is unclear or you need help with something feel free to ask.

[MarJMue]

I hope it's ok for you that I implemented the test and did a few changes myself.
I am working on importer stuff right now and would like to have this merged.
Thank you very much for your contribution.

[quentintanguy]

I hope it's ok for you that I implemented the test and did a few changes myself. I am working on importer stuff right now and would like to have this merged. Thank you very much for your contribution.

Totally! Thanks a lot! Sorry, I am still a github supernoob...

[MarJMue]

I am still a github supernoob...

No shame in that, everyone has to start somewhere.
Let me know if you want to contribute something else, or have any suggestions for improvements.