This morning, the DAS tuning performed in the past week has been reset and 'old' standard values have been settled (see table below).
|
| 'old' standard | CH [W] | INNER DAS [W] | OUTER DAS [W] |
|---|---|---|---|---|
| W | on the ITF | 0.046 | 0.150 | 1.596 |
| on the pickoff | 0.284 | 0.025 | 0.260 | |
| N | on the ITF | 0.104 | 0.340 | 3.77 |
| on the pickoff | 0.635 | 0.055 | 0.613 |
The ITF locked in LN3 at 09.21 UTC and then unlocked at 12.43 UTC (see main ITF behaviour in fig.1).
Unfortunately, when we tried to relock, the fringe appeared to be too high to proceed with the lock acquisition.
As a result, we spent the afternoon re-tuning the DAS in CARM NULL 1f with the aim to:
-
Maximize the sideband power
-
Minimize B1p
- Minimize the 56 MHz unbalance
We left the following settings for the night:
-WI IN+OUT (pickoff)=0.31 W
-NI IN+OUT (pickoff)=0.58 W
To be verified at the end of the thermal transient.
The common RH steps were skipped to avoid mixing effects.
