Continued from klog23777.
Yarm ASC was relocked. I don't know why the results were totally different yesterday, but it is possible that it was clipping. Today the transmission power was 1.02 and the reflection power was 0.21.
I checked sensing matrix and coupling. I got the same results of sensing matrix as before. Coupling was very little.
I measured U.G.F and spectrum. IY and EY mirrors increased noise and TRANS power decreased noise by 0.01 on the low-frequency side when ASC was turned on.
Sensing matrix : The result is almost the same as before.
Before is klog23230. After is /users/Commissioning/data/ASC/2022/REFL_WFS/Yarm/Sensmat/230202/TF_ASC_Yarm_REFLWFS_OPLEV_{ITMY, ETMY}_{P, Y}.xml
| DoF | IY_PIT | EY_PIT | IY_YAW | EY_YAW | ||||
| before/after | b | a | b | a | b | a | b | a |
| QPD1 17MHz PIT | 775.671 | 910.453 | -1339.92 | -1380.21 | ||||
| QPD2 17MHz PIT | -1944.91 | -1953.86 | 119.116 | 159.244 | ||||
| QPD1 17MHz YAW | -1359.92 | -1354.48 | -1486.03 | -1316.7 | ||||
| QPD2 17MHz YAW | 2472.84 | 2484.28 | 911.57 | 971.019 | ||||
Coupling : Couplings are almost small. (DHARD→ETMY, DSOFT→ITMY)
/users/Commissioning/data/ASC/2022/REFL_WFS/Yarm/Sensmat/230202/{ITMY, ETMY}_{PIT, YAW}.xml
U.G.F : I could measure U.G.F of DSOFT(ITMY). But U.G.F of DHARD was measured halfway because U.G.F is lower so it takes a long time to measure. The phase margin of all degrees of freedom is more than 50deg, which is stable.
/users/Commissioning/data/ASC/2022/REFL_WFS/Yarm/OLT_WFS_OPLEV/{DHARD_P,DHARD_Y,DSOFT_P,DSOFT_Y}.xml
| DHARD_PIT | DHARD_YAW | DSOFT_PIT | DSOFT_YAW | |
| U.G.F[Hz](Rough value) | 0.06 | 0.06 | 0.09 | 0.11 |
Spectrum: IY, EY mirrors (OPLEV signals) increased noise on the low-frequency side when ASC was turned on. Also, QPDs of TRANS increased noise a little on the low-frequency side, especially in PIT direction. However, Yarm frequency noise remained the same with ASC turned on. And, the low-frequency side of TRANS power decreased noise by 0.01.
/users/Commissioning/data/ASC/2022/REFL_WFS/Yarm/OLT_WFS_OPLEV/Spec_YarmASC_ONOFF.xml
About WFS DC offset: This time, the WFS DC offset was measured when the ADS was turned off, and I inserted it into WFS filter offset. But even with the filter offset turned off, the ASC in all degrees of freedom did not lock loss. I checked the transmission power(K1:LSC-TR_IRY_NORM_OUT_DQ) with or without the filter offset. Both results were almost the same. (I will consider this again later.)
| transmission power | |
| With the filter offset | 1.013 +/- 0.011 |
| Without the filter offset | 1.014 +/- 0.013 |
I put the time series of when ASC turned on after removing the tilt of IMMT2 and PR2 moved by ADS. The ASC kept for about 3 hours. (This was without the filter offset) However, I am concerned that the transmission power decreased slightly.
