The filter cavity was having a hard time locking, and it looks like the FC green trans power has been dropping slowly over the last 3 weeks, which seems to be caused by a drop in the SHG power from around 100-110 mW down to 77 mW .
I adjusted the picos and the SHG temperature, and recovered the SHG power to 86 mW, so there is still a lot of missing power. The filter cavity locked after this.
I've added a template for this adjustment to userapps/sqz/h1/Templates/ndscope/SHG_alignment_temp_adjust.yaml
Jennie W, Ryan C, Sheila
Ryan and Jennie saw that the filter cavity had trouble locking again. We looked at the filter cavity transmission and launched power now compared to 10 days ago. The launched power has dropped to 71% of what it was (after my slight improvement this morning), and the transmitted power is 69% of what it was. This means that the main reason the filter cavity tranmission has decreased is the lower injected power (due to SHG power drop), not a filter cavity alignment problem.
The guardian has a checker that the filter cavity is locked in green when transmission is above 60uW, which we lowered to 50uW in the GR_LOCKED checker. With the lower transmission the power was sometimes dropping below 50uW, so this would help. We will see what happens with the SHG power over the next few days.
