[RASMB] Optima AUC Interference optics question

[Jeff Arthur]

Hi Everyone,

I am having an issue with the interference optics on my Optima and I am hoping to get any advice on how to troubleshoot.  The issue is screenshot below, which shows two successive scans on each of two cells. My last couple runs have a blip at ~6.5 cm.  It is present in every cell, so I assume that it is instrument related.  At radial positions lower than the blip, the fringe shift is inconsistent between successive scans, which is creating difficulties in analyzing the results, even if the region immediately surrounding 6.5 cm is excluded from the raw data.  It's probably coincidental,  but I also noticed that the revolution counter decreased significantly immediately before this issue cropped up.  Before the issue it was ~550,000, and not it is ~450,000.

Thanks for the help!
Jeff

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