(CoreyG, DanielS)
At 1925utc, H1 dropped out of Observing due to the Squeezer. After a couple minutes, could see that the MANAGER & LO_LR nodes were cycling and not getting anywhere.
Wiki First
At this point, I opened the Troubleshooting SQZ wiki's "Can't Get To FREQ_DEP_SQZ" section. From this, I took MANAGER to NO SQUEEZING and then opened up all the SQZ Nodes.
At this point I notice the OPO_LR node which had been green is actually also cycling (but not as fast as the MANAGER & LO_LR. And OPO_LR was also showing a User Message, BUT it displayed too quick that I had to take a screenshot really quick to catch it. This node would hang out at the NOMINAL state (LOCKED CLF DUAL), drop out from this, display a message(s) for 1sec and then return to nominal state....all within a minute or so. There were actually 2 messages, they were to the best I could see (also attached):
- pump fiber rej power in ham7 high, nominal 35e-3, align fiber pol on sqzt0
- Disabling pump iss after 10 lockloss counter. Going to through LOCKED CLF_DUAL_NO_ISS to turn on agai
At this point, I started diving into medms for anything related to the shy messages above. "pump fiber rej power" gave me the most info for where to look, but at this point, I also wanted to do an alog search.
Then Alog Search
I searched OPO_LR, where I focused on an alog from (1) RyanS which referenced a Tony alog and (2) RyanC. These three alogs narrowed my focus and had me looking at:
- HAM7 Fiber Rejected Power signal
- SQZT0 waveplate
The Rejected power has been trending for the last month+ up to a max value around 3.0 (where it starts from about 0.03). I wasn't totally sure I had the scenario right, so at this point I reached out to Daniel (main contact for SQZ on the Call List).
Phoning Daniel For Help
After giving a summary the best I could, Daniel logged in and started looking. Some of the main points he mentioned:
- Fiber polarization
- Did not have enough green power
- Running out of range
- Crystal may be degrading
- Need more Green power!
With all that said,m he was able to get the LO_LR node to its nominal state, but he mentioned we could also fix the Fiber Rejected Power (atleast until the new year or about a week!). So he started to work on this. And this ended up being what was done by RyanS in his alog. See attached for image showing which waveplate/picomotor he adjusted on SQZT0 along with the HAM7 Fiber Rejected Power signal he watched & reduced. See attached for zoom in of the rejected power signal adjusment he made.
Daniel mentioned there will probably be a nead to make adjustments out on the table, but this change can get us through the holiday break.
Return to OBSERVING at 2056utc
