Today we pushed calibration report 20250823T183838Z, which updates the calibration model after changes to the actuation (ESD bias change) and sensing (SRC alignment offset change).
These are the steps I took (and two mistakes I made):
- [several days ago] ran
pydarm report --regen 20250823T183838Zwith the ESD bias and drivealign L3 L2L gains updated in the ini file. I checked to make sure the results were sensible. There is a change in the sensing function at low frequency, probably from an L2A2L related change.- note, we checked with the usual sqz "brontosaurus" measurement that the SRCL offset does not need to be updated. Any appreciable spring in the sensing function now is not due to SRC detuning.
- [yesterday] ran
pydarm report --regen 20250823T183838Zto get the GDS filters, checked the GDS filters to ensure they looked normal - [today] ran a broadband PCAL measurement, to get a "before" measurement of the systematic error
- we had been locked 41 hours at this point, so it's safe to say we were thermalized :)
- committed the report,
pydarm commit 20250823T183838Z --valid --message 'new calibration push, new ESD bias and SRC ASC offsets' - exported the report
pydarm export --push 20250823T183838Z - uploaded,
pydarm upload 20250823T183838Z - restarted gds,
pydarm gds restart- I marked the GDS restart time as 8:13 local
- waited for GDS to restart
- I was watching the CDS screen for the CALCS model, and once the filter modifications were detected, I reloaded the model, which should load in the appropriate filter changes
- MISTAKE 1: Jeff and I noticed that CAL DELTA L looked very weird and miscalibrated. We realized that the
H1:CAL-CS_DARM_FE_ETMX_L3_DRIVEALIGN_L2L_GAINhad not been updated with the new drivealign gain. Once I updated it, CAL DELTA L then looked correct- find the screen to check this via sitemap>cal cs>DARM calib> actuation function>ETMX actuator model>L3 drivealign
- Then, I waited and watched the grafana to see when the line monitoring came back online, which a sign that GDS is up and running
- MISTAKE 2: it seemed to be taking a suspiciously long time for grafana to come back online. Joe suggested I check if GDS is available in DTT. It was. I realized I had the grafana page set to "analysis ready" and we were out of observing. Once I switched the setting to "locked", indeed GDS had been back online for 10 minutes at that time.
- this only delayed the process, but it means we will go over time by a few minutes
- I ran the second broadband, and great success! The systematic error has improved, and is now 2% or less.
- Tony then proceeded to run the simulines measurement.
The attached plot compares the before and after PCAL broadband to GDS CALIB STRAIN. Tony will post the usual alog about the simulines measurement once it is complete.
Sadly, we lost lock mid-simulines measurement. However, the broadband pcal measurement showed success, so we are happy to keep this calibration and we will (hopefully) get simulines Saturday.
Here is the same plot as above, except with PCAL/GDS instead of GDS/PCAL.
We've had two locks since this push, and it appears the systematic error during thermalization is even lower than it was before. We updated the SRCL offset during thermalization, partially because it reduces the systematic error. It appears we do not need to update the thermalization servo, as the systemic error of the 33 Hz line is 2% or less during thermalization.
