The increase of LN1/HP has been seen thanks to the run monitoring data (see plot of the ratio at 541.6 Hz for WE, coilU).
Looking at the raw data, we found that the mirror actuation gain in LN1 mode has been changed between July 20th and 22nd. This change was not documented in the logbook.
A direct bad consequence is that the horizon has been overestimated and h(t) underestimated by 33% since July 22nd.
The hardware injections were also too strong by 33%, which was compensated by the 33% underestimation of h(t) such that the HI signals were recovered with correct amplitude.
This is just a scaling factor without frequency dependence.
Around 16h45 LT (with ITF unlocked), the following processes have been updated:
- TF+sensitivity measurements (in /virgoDev/Cali/v0r3p9),
- lastTF.vect was recalculated such that HorizonTF takes the new calibration (since 17h11 LT)
- Hardware and blind injection systems,
- h(t) reconstruction.
