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Reports until 08:06, Wednesday 08 January 2014
H1 ISC
kiwamu.izumi@LIGO.ORG - posted 08:06, Wednesday 08 January 2014 - last comment - 08:09, Wednesday 08 January 2014(9150)
PRX locking: PR2 and PRM aligned to the newly aligned PR3, some optics oscillating in pitch

After the alignment of PR3 (see alog 9146), I aligned PR2 and PRM to get PRX flashing with the infrared light. The resultant alignment sliders are shown in the attached.

I could lock PRX quite smoothly, but it seems that some optics are oscillating in pitch by a non-negligible amount. Due to this, the intracavity field spatially wobbles by almost its beam size in pitch according to the CCD camera attached on BS's chamber. In this condition, the intracavity power observed by the POP_A QPD fluctuates more than 10%. We need to identify which optic is the culprit by using the oplevs and witness sensors. It seems to me that it is hopeless to try locking PRMI without improving this wobbliness.

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kiwamu.izumi@LIGO.ORG - 08:09, Wednesday 08 January 2014 (9153)

An additional note:

The spatial beam motion was observed by introducing an intentional misalignment in ITMY and BS to let the ITMY reflection beam hit the BS baffle which is monitored by the BS CCD camera.

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