When Kiwamu locked PR-X (CH16), POP_A (CH1-7) saw some decent beam, about right in PIT and off in YAW.
POP_B (CH9-15) also saw something, it's not clear if it was the real beam or some ghost, the power is about a factor of 10 smaller than POP_A, and mostly in seg1 and 2.
Anyway, the important thing is that the POP_A already see the beam and POP_B is close.
Don't use pico to center these, though, as POP sled might be a good initial alignment reference.
We should first align the IFO to the POP sled and see if it makes things better. POP sled was aligned perfectly in the last days of HIFO-X/Y. Though a beam splitter was inserted after the vent, the insertion procedure was written such that the sled centering is preserved.
The above entry is simply wrong.
When I centered these QPDs before vent, with 45dB whitening gain and with a straight-shot beam, DC sum of QPDA was something like 56 counts with a bogus calibration factor of 0.0056 that is in QPD segment filters (screen shot from before the vent, May 30).
Since then we installed 90:10 to attenuate the light by a factor of 10, but increased the PSL power by a factor of 5, so when the beam hits the QPD I expect something like 28 counts, but we got 0.4 at most, it's a factor of 70 smaller than expected.