Virgo Logbook

After the ITF recovery we start the squeezing shift by realigning the squeezer. As usual we inject 5Hz line with the actuators and we maximize the second harmonic in the signal SDB2_B1_PD2_7MHz_mag. After this process the new SLOW_AA set points are

CamFarX = -120 um
CamFarY = 345 um
CamNearX = -220 um
CamNearY = 125 um

After the realignment we start to characterize the measured squeezing level into the interferometer at different values of the OPA green pump power. For each power we have the following data set

a phase scan (120s shutter closed, 360s of phase scan, 120s shutter closed)
we tuned the phase to have the maximum squeezing level and we open the shutter for 5 mins
we tuned the phase to have the maximum anti-squeezing level and we open the shutter for 5 mins
we closed the shutter for 5 mins

In the following we list all the different data sets:

Level 1

sqz = -2.7 dB asqz = 6.5 dB (around 10dB injected)
green power = 4.5 mW
phase sqz = 2.27 rad phase asqz = 1.05 rad
Phase scan: GPS: 1234029610 (120 + 360 + 120 = 600s)
squeezing: GPS: 1234030803 12 Feb 2019 18:19:45 UTC (12 Feb 2019 19:19:45 CET)
antisqueezing GPS: 1234031196 12 Feb 2019 18:26:18 UTC (12 Feb 2019 19:26:18 CET)
shotnoise GPS: 1234031539 12 Feb 2019 18:32:01 UTC (12 Feb 2019 19:32:01 CET)

Level 2

sqz = -2.97dB asqz = 8.85dB
green power = 6.75 mW
phase sqz = 2.07 rad, phase asqz = 0.92 rad
Phase scan: GPS: 1234032639 (600s) gain 100 too high
Phase scan: GPS: 1234033678.75 (600s) gain=70
Squeezing GPS: 1234034641 12 Feb 2019 19:23:43 UTC (12 Feb 2019 20:23:43 CET)
Antisqueezing GPS: 1234035791 12 Feb 2019 19:42:53 UTC (12 Feb 2019 20:42:53 CET)
Shutter closed GPS: 1234036142 12 Feb 2019 19:48:44 UTC (12 Feb 2019 20:48:44 CET)

Level 3

sqz = 2.85dB asqz = 11.2dB
green power = 9mW
sqz Phase = 2.29 rad, asqz phase = 0.92 rad
Phase scan: 1234039465.58 600s Gain = 50
squeezing GPS: 1234040559 12 Feb 2019 21:02:21 UTC (12 Feb 2019 22:02:21 CET)
antisqueezing GPS: 1234042815 12 Feb 2019 21:39:57 UTC (12 Feb 2019 22:39:57 CET)
Shot noise: GPS: 1234043575 12 Feb 2019 21:52:37 UTC (12 Feb 2019 22:52:37 CET)

Level 4

sqz = -2.27 asqz =4.45 dB
green power = 2.3 mW
sqz phase = 2.27, asqz phase = 0.95
Phase scan GPS: 1234046498.65 Gain = 100 Squeezing = 1234047389 12 Feb 2019 22:56:11 UTC (12 Feb 2019 23:56:11 CET)
antisqueezing 23:07:00 UTC
shotnoise 23:11 UTC

Level 5

asqz = 5.3 dB, sqz = -2.3 dB
green power = 3.3 mW
asqz_phase = 0.95 rad, sqz_phase = 2.3
Phase scan GPS: 1234048663, Gain = 100

We found that the squeezer was misaligned. Probably this was caused by an ITF unlock that happened when the automation (SQZ_MAIN) was in Pause, so we realigned the squeezer.

After the alignment the set points of the SLOW AA are:

CamFarX = -148 um
CamFarY = 345 um
CamNearX = -160 um
CamNearY = 100 um

Level 5 After realignment

squeezing level = -2.67dB, asqz = 5.48 dB
Phase scan GPS: 1234053969
asqz_phase = 0.87, sqz_phase = 2.24
We add a CC loop boost and we re-perform the scan, GOS = 1234057206.07

WIth this level and without the boost we performed a CC noise injection with a white noise (amplitude = 3e-6V). GPS = 1234055753 (1 min of measurement)

Finally, to evaluate the magnitude of the phase drift and to start to study the coherent control phase stabilzation we added a dither on the CC driving noise with frequency 0.1Hz and Amplitude 0.05V (GPS: 1234051169)

To remove it go to the SQZ_CC_Ctrl server, Driving noise, Set Noise Amplitude, Noise Amplitude = 0

We left the squeezer engaged with the shutter open during the night, if you want switch it off it is enougt to send the SQZ_MAIN metatron node to SQZ_REST_POSITION, We left the ITF in autorelock failsafe

The analysis of the data will be reported later