Jennie W, Keita K, Jason O, Jenne D,

Once we got the locking of JAC and IMC working at 20W this morning, Keita went into the chamber while we had PRMI aligned to check the POP beam alignment in HAM1.

We had trouble keeping the IMC locked when Keita was moving next to the chamber, JAC occasionally unlocks but is staying locked for long periods. I hypothesise that JM3 moving around is more of a problem than JM1 because of this. Eventually we managed to stay locked with 4W while Keita was in chamber. Over this period Keita realised the beam was mis-aligned coming out of the POP periscope and so we used PR2 and PR3 yaw to walk the beam back till it was well centred on AS AIR camera and we still saw flashes. Eventually we mis-aligned ITMY and just used PRX flashes. We had to move 10 microradians on PR2 and then correct with 1 microradian on PR3 to maintain the alignment.

I put the power up to 10W from 4 W and we saw a power change on ASC-POP_X.

To see if we could recover alignment onto POP-X with PM1 we put the PM1 yaw up to a high value so it was railing and we did see some counts on ASC-POP_X QPD SUM but we cannot point the beam onto the diode before PM1 rails so we undid this.

The day ended with a total move of -120 on PR2 yaw, -12 on PR3 yaw, -8.1 mircoradians on PR3 pitch, and +81 microradians on PR2 pitch. Keita can now see the beam on the side of the ASC POP X QPD.

The pitch changes we did at the end of the day were to try and improve the steering to ASC POP X but we didn't get time to optimise this so we can undo them tomorrow if necessary.

Summary: Checking POP is hard as the IMC will unlock very easily if someone is in HAM1, probably due to shaking of JM3. We need to work out if we trust the PRC alignment axis or if we want to cross-check it with something else (like the ALS beam from the X-arm) before we continue debugging.