jennifer.wright@LIGO.ORG - posted 16:07, Friday 14 June 2024 (78446)
Checking SRC (SEC) alignment before and after April 22nd and comparing with SRC alignment now
I looked at the SUS-{SR2,SR3,SRM_M1_DAMP_{P,Y}_INMON channels for a period on the 21st April before the OFI, and after we had re-aligned through the OFI to rcover our optical gain on the 25th April after the OFI burn.
I have compared these to the drift in alignment in the signal extraction cavity yesterday. This is partly to figure out why we have to keep retuning our SRCL feedfoward.
| Date | Mirror | delta pitch value | delta yaw value |
| 21st April | SR2 | 2 | 0.8 |
| 25th April | SR2 | 3 | 2 |
| 13th June | SR2 | 3 | 3 |
| 21st April | SR3 | 0.5 | 0.9 |
| 25th April | SR3 | 0.3 | 6 |
| 13th June | SR3 | 0.5 | 0.3 |
| 21st April | SRM | 13 | 6 |
| 25th April | SRM | 23 | 7 |
| 13th June | SRM | 7 | 7 |
The only angular degrees of freedom that changed significantly between these dates were:
- SR3 yaw which was changing during lock about 6 times its normal drift on the 25th vewrsus how much it changed during the lock on the 21st. Yesterday its drfit during lock seems back to its value before the OFI burn.
- SRM pitch drift seems to vary a lot between these three different locks. Not sure what we can learn from this.
Images attached to this report
