After solving the problem on the BS DSP, DAS tuning started.
9.10 UTC: LN3
9.35 UTC: WI DAS INCREASE (+15 %)
10.01UTC: unlock
10.53 UTC: the sidebands was low in the CITF preventing the lock acquisition→ increase WI CH by 15 %
The powers applied in this step are summarized in the table below.
| STEP6_S 12.39 UTC | CH [W] | INNER DAS [W] | OUTER DAS [W] | |
| W | on the ITF | 0.078 | 0.090*(1+15/100)=0.119 | 1.615*(1+15/100)=2.45 |
| on the pickoff | 0.48 | 0.0169*(1+15/100)= 0.0194 | 0.347*(1+15/100)=0.399 | |
| N | on the ITF | 0.091 | 0.266 | 2.972 |
| on the pickoff | 0.561 | 0.044 | 0.484 |
After that, it was possible to reach CARM NULL 1F but the misbalance of the upper and lower 56 MHz sidebands on B1p prevented the lock in low noise, thus I reverted the increase of the WI DAS power and, following Paolo’s indication, I slightly decreased the NI DAS by 10 % (at 13.28 UTC).
| STEP7_S | CH [W] | INNER DAS [W] | OUTER DAS [W] | |
| W | on the ITF | 0.078 | 0.104 | 2.13 |
| on the pickoff | 0.48 | 0.0169 | 0.347 | |
| N | on the ITF | 0.091 | 0.186*(1-10/100)+0.08= 0.247 | 1.172*(1-10/100)+1.8 =2.85 |
| on the pickoff | 0.561 | 0.036*(1-10/100)+0.013= 0.0402 | 0.190*(1-10/100)+0.293= 0.464 |
The ITF unlocked during different steps of the lock acquisition, thus, the DAS powers have been re-settled to STEP 5S (at 15.22 UTC).
| STEP5_S | CH [W] | INNER DAS [W] | OUTER DAS [W] | |
| W | on the ITF | 0.068 | 0.104 | 2.13 |
| on the pickoff | 0.418 | 0.0169 | 0.347 | |
| N | on the ITF | 0.091 | 0.266 | 2.972 |
| on the pickoff | 0.561 | 0.044 | 0.484 |
Sorry for the delay of the start of the afteroon activity.
