OMC Scan with PSL beam

Jennie W, Sheila,

 

We turned off the 9 and 45 MHZ sideband EOMs and unplugged the 118 MHz modulation at the PSL racks. See this alog for how to do this.

 

We locked the IMC and mis-aligned ITMX.

 

DC centering loops 3 and 4 were turned on.

 

Sheila took the OMC lock guardian to PREP OMC scan and turned on the OMC ASC.

We waited for this to converge then turned it off.

 

We turned input power up to 10W from 2W and then locked the OMC in length manually by using the PZT offset slider to search for a high peak ~ 15mA.

After finding it we turned on the locking with a gain of 24 and the boost and int filters on (we checked the settings we needed in the guardian as we couldn't get the OMC guardian to lock it for us).

 

Then we turned off the OMC ASC.

 

We tuned up the OM3 and OMC alignment slightly to maximise the power on OMC-DCPD_SUM_OUTPUT and minimise it on OMC-REFL_A_LF_OUT16.

OM3 was moved down in yaw only from -108 to -117 and OMC was moved down in yaw from 210.5 to 195.5 and down in pitch from 350.4 to 340.4. The final values for the sliders are here.

 

Quiet time locked after aligning 16:21:03 UTC - 16:24:13 UTC

OMC-REFL_A_LF_OUT16 = 0.652644 mW

OMC-DCPD_SUM_OUTPUT = 15.6162 mA

 

Quiet time unlocked 16:25:31 UTC -16:27:35 UTC

OMC-REFL_A_LF_OUT16 = 30.106 mW

OMC-DCPD_SUM_OUTPUT = 0.000456763 mA

 

We took the IMC guardian offline and shuttered the green light going into both arms at the ISC tables, and with ISC_LOCK guardian in idle so it wouldn't keep trying to relock IMC.

Quiet time dark measurement 16:43:38 - 14:46:19 UTC

OMC-REFL_A_LF_OUT16 = -0.0132979 mW

OMC-DCPD_SUM_OUTPUT = -0.00106226 mA

 

The scan template is saved as /ligo/home/jennifer.wright/Documents/OMC_scan/2024_04_16_OMC_scan.xml

With the references for the time series of the three pertinent channels as:

Ref 0 OMC-DCPD_SUM_OUT_DQ

Ref 1 OMC-PZT2_EXC

Ref 2 OMC-PZT2_MON_DC_OUT_DQ