Abstract:

We checked the beam spot on POM2 after finely aligning PRM.
The beam spot seems almost center in horizontal direction and slightly high (but maybe acceptable) in vertical direction.
We also confirmed REFL beam hits PDA1 without any other alignment.

Detail:

Since we don't have enough time today, we just aligned IMMT1, IMMT2, and PRM, and started the beam check of reflection beam.
First, we checked reflection beam at IFI output port and found that beam is shifted in -Y +Z(upper) side.
So, we changed PRM alignment: from -120 to -220 and -60 to -170 in pitch and yaw, respectively.
After that, we checked the beam at POM1 and POM2.

As reported in the previous check (klog28779), beam spot on POM1 seems center.
Also, beam spot on POM2 is not so far from the center: almost center in horizontal direction and slightly high in vertical direction (fig2).
Then, we checked REFL DC PD signals and confirmed that REFL PDA1 have a light (fig3: between T cursors, shutter was closed).

So, alignment of POM1, POM2, and REFL do not seem so bad in terms of the main IFO reflection beam.