cheryl.vorvick@LIGO.ORG - posted 12:21, Thursday 21 January 2016 (25075)
IO IM2 alignment changes after a HAM2 ISI trip - January 20th power outage
The LHO IM (IM1, IM2, IM3, IM4) alignments change, for the same alignment offset (drive), after a HAM2 ISI trip, or like yesterday, a power outage.
IM2's algnment changes the most, so I have only include it in this alog.
The first attachment is a chart that shows how the IM2 alignment changed, and how much IM2 and the HAM2 ISI shook during this event, summary here:
| IM2 pitch | changed | -33.7urad |
| IM2 yaw | changed | -5.5urad |
| IM2 length | shook | 0.4mm |
| IM2 pitch | shook | 9.9mrad |
| IM2 yaw | shook | 8.8mrad |
| HAM2 ISI X | shook | 8.8mm |
The second attachment is the full data trends for these channels (not in the same order) during the shaking.
At LHO, it is a requirment to check IM alignments after a HAM2 ISI trip, because these alignment shifts regularly occur after the optics experince the shaking.
Other alignment change / shaking events to be posted.
Images attached to this report
