Attached is a mdoescan of the DBB HPO path after some alignment attempts were made. It seems that TEM01/10 modes seems to be within reasonable values. Vertical alignment into the PMC seems to be slightly better than reference. Horizontal was marginally worse yet locking of the PMC was still not possible.
This scan was taken so we could have an idea of where we are after today's alignment work. Based on what I see, the HPO path of the DBB looks pretty good. Higher order mode power of 6.9% is reasonable, TEM01 (vertical alignment indicator) looks nice and low, although the TEM10 (horizontal alignment indicator) looks a little high, but not too bad. The mode matching peaks (the 2 larger peaks left and right of center) both look good when compared to the reference. All in all I think the HPO alignment into the DBB is pretty good. That said, as Ed says above, we are still unable to lock the DBB PMC. At this point I'm not sure what/where the problem is. Based on this mode scan I don't think it's an alignment/mode matching issue. Will have to think on this one...
No work was done on the Front End (FE) path today, will work on that once the HPO path is fully up and running.