O4 Commissioning Task List

This is a list of things to do for each commissioning stage for O4.

Each stage include ASC.

Preparations

Tune f1, f2, f3 frequencies to IMC FSR
Replace all the in-vac steering mirrors and pick-off mirrors to proper ones JGW-T2112592
Replace all the beam splitters in in-air optical tables to non-polarizing beam splitters JGW-D2112956
- This is necessary to estimate the polarization content of the interferometer correctly (without too much confusion)
Install polarization optics to backward POP or POS, and TRY and TRY.
- This is necessary to estimate the arm cavity round-trip loss correctly JGW-T2011633

Measure the finesse at room temperature and at cryogenic temperatures, for both 1064 nm and 532 nm.
Measure the round-trip loss by taking into account the effect of birefringence correctly.
- Measure the beam spot position dependence
Measure the mode-matching for both 1064 nm and 532 nm.
Tune the Gouy phase separation between two QPDs at TRX.
Measure the alignment sensing matrix at REFL/AS/TRX, for ITMX and ETMX.
- Try closing ASC loops.
Measure modulation depths for f1, f2 and f3.