I see no evidence of anything radically different from my PSL table optical characterization in the IMC transmitted beam, see Attachment #1. The lines are just a quick indicator of what's what and no sophisticated peak fitting has been done yet (so the apparent offset between the transmission peaks and some of the vertical lines are just artefacts of my rough calibration I believe). The modulation depths recovered from this scan are in good agreement with what I report in the linked elog, ~0.19 for f1 and ~0.24 for f2. On the bright side, the ALS just worked and didn't require any electronics fudgery from me. So the mystery continues.