aLIGO LHO Logbook

H1 OpsInfo

jennifer.wright@LIGO.ORG - posted 09:28, Tuesday 02 September 2025 - last comment - 11:12, Wednesday 03 September 2025(86623)

Instructions for running DARM OFFSET STEP to do output loss meas with hot OM2.

Test for Thursday morning at 7.45 am, assuming we are thermalised.

In NLN.
Turn off OMC ASC:
- sitemap -> OMC -> OMC Control -> turn MASTER GAIN slider to 0 (its blue and on the bottom centre of screen).
Run DARM offset step:
- Go to /ligo/gitcommon/labtutils/darm_offset_step
- run:

conda activate labutils

python auto_darm_offset_step.py

Wait until program has finished ~20 mins.
Turn OMC ASC back on by putting master gain slider back to 0.020.
Heat up OM2 heater (~ 3 hours):
- IFO out -> OM2 -> change H1:AWC-OM2_TSAMS_POWER_SET value to 4.6.
After power has leveled out on H1:AWC-OM2_TSAMS_THERMISTOR_1_TEMPERATURE and H1:AWC-OM2_TSAMS_THERMISTOR_2_TEMPERATURE, turn off OMC ASC again by putting MASTER GAIN slider back to 0 on OMC Control screen.
Run auto_darm_offset_step.py again.
Put OM2 heater H1:AWC-OM2_TSAMS_POWER_SET back to 0.
Test done, wait for thermistors to level out again.

Comments related to this report

jennifer.wright@LIGO.ORG - 11:12, Wednesday 03 September 2025 (86716)

Link

Test for Thursday morning at 7.45 am, assuming we are thermalised, rewrote instructions above and took out last part.

In NLN.
Turn off OMC ASC:
- sitemap -> OMC -> OMC Control -> turn MASTER GAIN slider to 0 (its blue and on the bottom centre of screen).
Run DARM offset step:
- Go to /ligo/gitcommon/labtutils/darm_offset_step
- run:

conda activate labutils

python auto_darm_offset_step.py

Wait until program has finished ~15 mins.
Turn OMC ASC back on by putting master gain slider back to 0.020.
Heat up OM2 heater (~ 3 hours):
- IFO out -> OM2 -> change H1:AWC-OM2_TSAMS_POWER_SET value to 4.6.
Open beam diverter.
- Go to sitemap -> LSC -> Beam Diverter -> Corner -> Press top right button labelled 'OPEN' under Corner_POP section.

Commissioners will turn off OMC ASC and close beam diverter once heating has finished then do DARM offset step and other tests before turning on ASC and opening beam diverter before cooling down OM2 again.