Reports: 

- DBB shutter open results in a huge noise bump issue

- peaks are smaller, but still there wtih DBB closed off

- PMC high voltage noise: (HV drive coherent, better readout--> peaks visible, realignment of PMC improved peaks / but hump is still there)

- coupling mechanism from PMC length offset to DARM unclear

- PMC UGF was 600Hz instead of 5kHz. going to (nominal) 5kHz made DARM noise worse.

- Reducing PMC loop gain further is not helping enough

- projection ~x2 below noise bump.

- PMC wrong polsarization light? (would be almost resonant, and therefore sensitive to PMC length noise) not clear how the coupling downstream of PMC works.

- Jitter spectrum looks smooth - thermally diven? Is so, other modes also produced... 20 mode...!

- picomotor steering into PMC to test...

- SRM: alignment affects jitter bump... !?

======================================================================

To do:

- 9MHz missing in reflection (x5 missing: (2W-50W we are loosing 2.5x)) - > find 1W of 9MHz (what was the conclusion for REFL9 gain?) 

- Low noise operaion at 12W, 24W (available in guardian)

- ER9 TCS configuration?

- PMC pole down

- Donut jitter verification? How?

Things to copy from LLO:

- Black glass for ETM camera to eliminate back-scatter

- ESD bias noise / zero crossing * run with ESD offset /reduced bias

- Compensation plate alignment ?

- PCAL switch (too much noise?)

"classical" tunings to be redone at operating point:

- A2L / ASC tuning

 -Aux loops feed-forward

=======================================================================

Timeline:

- HPO: Earliest: Monday 10/24

        - Option: 12W low power test first

- ER10 start LLO Oct 31 / LHO 10 days later

========================================================================