SHIFT GOAL:

The goal was to perform several CC scan at different SR angle. Nevertheless, due the not optimum condition of the MZ and OPA (waiting for the retuning) we decid to perform a couple of scan without changing the SR angle to check the SQZ alignment-

SHIFT activity:

We started at  16:00 UTC and to not interfere with the ITF and risk to unlock, we manually injected the SQZ. 

• System initial status: ITF LOW NOISE 3; SQZ_MAIN @SQZ_Locked_NO_FC

• 16:10:39 EQB1  fast shutter opened (process: SQZ_ctrl/shutter ‘open’)

After that the CC_loop was engaged and then  the AA (process: SQZ_PLL_AA/ Matrix and Filter ‘AA dither enable’).

• started a CC 4MHz phase scan @ 16:52. 

  • time per point = 6 s

  • - initial phase  = 20 degree

  • - final phase = 230 degree

  • - phase steps = 1 degree

  • - random phase = False

  • - Closed shutter sleep time = 120 s

  • - AA closed on dither = False

  • - cc loop gain   = 75000.0

N.B: No glitch during the scan, it was just before and after (see plot)

In meantime Henning checked the MZ and changed lowered again the offset at 0.035 V due to the humidity  misalignment that spoiled the contrast and induced the set point near the actuator saturation. After the Henning action we redid the scan. 

We stopped at 19.25 after that some data have been collected at the CC phase value corresponding to the SQZ and ASQZ, or better to the minimum and maximum values in the BRMS range @210 MHz and in other ranges.

Further data  and plot in the following comments.

Today Henning switch in SQZ mode.

I optimized the SQB1 HWP to send SQZ  toward HD detector

I measured 2.6 of parametric gain i.e. 8.3 dB of generated SQZ. In particular the 4MHz mag had respectively 8.26mV of Max and 3.18mV of min

I measured 7.95 dB of ASQZ with CC phase of 0.69 rad and 5.65 dB of SQZ with CC phase of 2.35 rad

The system is ready for the tomorrow shift

Today at 19:12 UTC Henning performed the switch from BAB to SQZ

From 23:19 UTC I started to check the SQZ level with HD detector (the retroreflector was already on)

I measured 5.6 dB of SQZ at 2.25 rad and 8.05 dB of ASQZ at 0.75 rad

Then I open the CC loop and I measure the parametric gain with the HD 4 MHz mag. The max was 8.25mV and the min was 3.16 mV. The ratio is 2.61 i.e. 8.3 dB of generated SQZ.

At 23:50 UTC I rotated the SQB1 HWP to inject SQZ into the ITF.

I left the system with the SQB1 Shutter closed and the SQZ_MAIN node in READY_FOR_FIS_INJECTION

I modified the coh_scan.py script in order to measure the parametric gain at the beginning of each scan: I added a delay of 5s between the shutter opening and the lock of the CC loop.

I left also the LO shutter closed.

After a tuning of the squeezer by Henning  i retuned the retroreflector alignment and I fine tuned the Sqb1_HWP2.

I measured the SQZ level on HD with retroreflector and I found:

• generated SQZ 8.75 dB
• ASQZ 8.25 dB
• SQZ 5.85 dB

In the process I wrongly moved SQB1_M21_H and V instead the Retroreflector. I came back but should be checked when the retroreflector will be again DOWN

The goal of the shift were:

• Recovery of the alignment after the shutdown and the decrease of the power
• Re-tuning of the automation SQZ_MAIN 
• Tuning of SQB1 and SDB1 HWPs

Actions performed:

• 15:26 UTC SQB1 Shutter Open with -1350000 steps
• We measured the level of SQZ on the HD detector during the opening of the shutter and it was at 4.5 dB and did not change during the opening
• We realized that the SQZ level gnerated by the OPA was very low 7dB.
• We contacted Henning and he retuned the temperature of the OPA
• After the tuning we measured with the parametric gain 7.5 dB of generated SQZ and 4.8 dB of SQZ with HD detector
• At 15:51 UTC we rotated the SQB1 HWP2 to inject SQZ light into the ITF
• The interferometer unlocked and we also realized that the OPA was no more able to relock
• Fiodor spotted that in the DET lab the humidity was very unstable and for this reason the OPA was too Misaligned (Fig1) 
• At 16:28 UTC Henning Changed the MZ offset at 0.05V and we could relock again the OPA. After this tuning we were generating about 8.5 dB of SQZ. During the rest of the shift the level of SQZ was decreasing due to the humidity drift
• After the relock We started to Inject the Squeezing into the ITF: we open the fast shutter and we found the right CC DAC offset that allows us to close the CC loop on B1, i.e 0.285V.
• We started to realign with the CC closed, the SQZ phase in ASQZ, i.e. 2.8 rad and by sending ramps to SQB1_MIRROR1,2_X,Y We could arrive at maximum 0.8mV of magnitude on B1_4MHz
• We tried to move horizontally SQB1 from -3500um to -2850 um and the level of mag increased up to 1.5 mV then the ITF unlocked again
• We profit of this situation to tune the SDB1 OFI HWP:
  • we set the DAC offset at 0.26V to have a beat note on HD between ITF spurious beam and the LO at about 650 Hz
  • we rotated SQB1_HWP_2 to send all the SQZ light again toward HD detector
  • Looking EQB1_HD_DIFF_AUDIO we moved by 100-200 steps per time the SDB1 OFI HWP, in total +550 steps with the aim to decrease the beat note on the spectum
• We did the same with the SQB1_HWP1 waveplate and we moved it in total by -450 steps
• In total we rotated by about 1deg each HWP reducing the beat note on HD by more than a factor 10. All these operation were performed in Carm nulll 1f
• After that the ITF relocked and we were able to close the CC loop gain 25000 and the AA loop reaching a 4MHz mag of about 1.72 mV. 
• We did the following measurements (fig 2 SQZ,ASQZ,Shot in spectrum and fig 3 in time domain):
  • ASQ @ 18:57 UTC phase 2.8 rad
  • SQZ @ 19:02 UTC phase 1.2 rad
  • Shot @ 19:08 UTC
  • We closed the LO shutter at 19:06 UTC
  • SQZ @ 19:23 UTC from shot to SQZ the BNS range increased by 0.5 Mpc
• We retuned also the slow CC loop. The demodulation phase was changed from 5.2 to 4.7 rad and the dither line was increased from 0.0005 to 0.001V
• The ITF unlocked and we tested the automation finding problems in reaching the state ready for FIS Injection. We realized that when the SQZ_CTRL setted the use of the ITF_Status to 1 the SHG unlocked. We modify the Squeezer locking matrix to avoid this.
• After that we where able to inject FIS into the ITF with the automation.
• We set the automation in SQZ_LOCKED and we performed a CC phase scan at 20:45 UTC (fig 4) From the phase scan we realized that the CC dither demod phase was wrong by 90 deg and we put it at 6.2 rad 
• After the phase scan we left the system in SQZ_INJECTED

The recovery of QNR is completed, the measured level of SQZ in the sensitivity was not high but the sensitivity curve was not optimized at high frequencies

We left the shutter open in SQZ_INJECTED. Here the instruction to remove it and close the shutter https://wiki.virgo-gw.eu/AdvancedVirgoPlus/QNRTutorialsSQB1_Sutter

Yesterday we measured the SQZ level in the three configuration with 8.75 dB of SQZ generated measured with the parametric gain. I had the impression that the squeezer was mistuned.

We measured

• Reflection from FCIM
  • SQZ: 5.25 dB
  • ASQZ: 7.7 dB
• EQB1 Delay Line:
  • SQZ: 6.1 dB
  • ASQZ: 8.1 dB
• SQB1 Retroreflector:
  • SQZ: 5.6 dB
  • ASQZ: 7.9 dB

Today Henning tuned the squeezer OPA temperature and now we have 8.6 dB of SQZ generated

• SQZ: 5.7 dB of SQZ measured with retroreflector
• ASQZ: 8 dB of ASQZ measured with the retroreflector
• SQZ: 6.3 dB with Delay Line
• ASQZ 8.2 dB with Delay line

Now the system is ready for the shift of tomorrow afternoon

Switch in SQZ and realignment of the HD

1) Henning switched in SQZ on Saturday 25. We found some problem in the translation stage process on VPM. We performed the shift using the graphical interface installed on Olwin machin
2) Once we were in SQZ I realigned the SQZ on the HD detector with the following steps:

• Align the FIlter cavity with green and IR
• Close the SC shutter
• remove EQB1_HD_MIR
• Look the channel EQB1_HD_DIFF_RF_4MHz_mag
• Move SQB1_M13_X and Y DOFs to increase increase the 4MHz beat note sideband on HD
• Once done this unclip the filter cavity reflection in the FI by moving SQB1_M22_X and Y picomotors
• Open SC Shutter and close IR AA loop
• Close SC shutter and iterate again with SQB1_M21_X and Y picomotors
• Close the CC and EQB1_HD_AA loops
• Move M21_X and Y and M13_X and Y withe EQB1 HD AA loop closed in order to maximize the mag (the phase was set to measure ASQZ)

3) Once done this we open CC and AA loop and we switched on the delay line on EQB1

• we close CC loop and set ASQZ phase
• we moved EQB1_DL_M4_X and Y and EQB1_DL_M5_X and Y with EQB1_ThorAct in order to maximize the magnitude
• once we reached a maximum we closed the EQB1_HD_AA loop and we continue to iterate with DL mirrors in order to fine tune the alignment

4) Realignment of the HD PDs: we religned the HD PDs with the aim to increase the HD CMRR:

• with DL in SQZ angle CC closed and HD_AA open
• move HD_PD1_X and Y and PD_2_X and Y with the aim to increase the mag, the SQZ Level and to reduce all the peaks in the EQB1_HD_AUDIO_DIFF spectrum

5) Once all the parameters were tuned with SQZ and DL configuration we rotated the EQB1 FI HWP1 to improve the quality of HD spectrum

We measured:

• with DL: 8.3 dB of ASQZ and 6.3 dB of SQZ
• with FCIM: 7.9 dB of ASQZ and 5.4 dB of SQZ

Still to do align the SQB1 Retroreflector

This entry is related to work performed between 12 and 15 November.

I completed the auomation working mainly on SQZ_MAIN process adding the following features:

• The possibility to Inject FIS or FDS in the Interferometer the difference is how it locks the filter cavity. To decide if you want to Inject FIS or FDS you should change a flag in SQZ_MAIN.ini file in the AUTOMATION_MODES group. The flag is named "fis_injection". You should put equal to True if you want inject FIS or False if you want to inject FDS.
  • "fis_injection=True": if you ask the state SQZ_LOCKED or SQZ_INJECTED. The system lock the filter cavity with green going in the state FLT_GR_AA_NOIR, then it Goes in the state Ready to FIS_INJECTION and then it locks the squeezer and perform the Injection
  • "fis_injection=False": if you ask the state SQZ_LOCKED or SQZ_INJECTED. The system lock the filter cavity with green going in the state FLT_IR_AA_FMODERR_TUNED, then it Goes in the state Ready to FDS_INJECTION and then it locks the squeezer and perform the Injection
• Added a rest position for the squeezer: the locking of the ITF is very long thus during the lock acquisition and dead periods we unlock the squeezer to save the OPA nonlinear crystal lifetime. This is done in the state READY_FOR_FIS_INJECTION and READY_FOR_FDS_INJECTION. In these state we leave the SHG and MZ locked and we unlock OPA and PumpPhase. From DOWN to these states the squeezer is locked to allow to lock the filter cavity on IR if needed.
• Added the SQZ_LOCKING and SQZ_LOCKED states. We relock the squeezer just before injecting it inot ITF. These states are commond both for FIS or FDS injection

Management of the shutters

We don't have a fast shutter at the end of SQB1, thus we need to use the shutters on EQB1 to protect the squeezer. The drawback is that when we close the EQB1_FAST_Shutter we can not Inject SC into OPA and use it to lock the cavity. Thus we arranged in the following manner:

• EQB1_FAST_SHUTTER (managed by SQZ_MAIN):
  • SQZ_MAIN in DOWN: is closed
  • SQZ_MAIN in FLT_DOWN, FLT_IR_AA_FMODERR_TUNED, FLT_GR_AA_NO_IR:  is open
  • SQZ_MAIN in READY_FOR_FIS_INJECTION, READ_FOR_FDS_INKECTION: is closed
  • SQZ_MAIN in SQZ_LOCKED is closed
  • SQZ_MAIN in SQZ_INJECTED is open
• SC_Shutter (managed by SQZ_FLT) is opened during the lock of the filter cavity in the state SQZ_FLT CONFIGURING_GREEN, we close it in the following states:
  • SQZ_MAIN in READY_FOR_FIS_INJECTION
  • SQZ_MAIN in HD_FDS_MEASUREMENT
• IR shutter and green shutter not managed by automation
• LO_Shutter not managed by automation but should be closed to Inject SQZ into ITF

Description of the new states:

• REAY_FOR_FIS_INJECTION:
  • this state is reached after the FLT_GR_AA_NOIR
  • we unlock the laser part SQZ_CC_Ctrl of the Filter cavity longitudinal control,
  • we prepare the SQZ_CC_Ctrl process to engage the CC loop and no more the longitudinal control of the filter cavity
  • we close the EQB1_FAS_SHUTTER
  • we unlock PumpPhase and OPA cavity
• REAY_FOR_FDS_INJECTION:
  • this state is reached after the FLT_IR_AA_FMODERR_TUNED
  • we unlock the laser part SQZ_CC_Ctrl of the Filter cavity longitudinal control,
  • we prepare the SQZ_CC_Ctrl process to engage the CC loop and no more the longitudinal control of the filter cavity
  • we close the EQB1_FAS_SHUTTER
  • we unlock PumpPhase and OPA cavity
• SQZ_LOCKED: here we lock the OPA and PumpPhase 
• SQZ_INJECTED:
  • Open EQB1_FAST_Shutter
  • Close CC loop on B1
  • Close AA loop between SQZ and OMC
  • Close the drift control of the CC loop on B1
  • Only if "fis_injection=False" once the shutter is open, before closing the CC loop, we re-put the filter cavity in the state FLT_IR_AA_FMODERR_TUNED

To test the automation I had to remove the SQB1 retroreflector and I did the following measurement with HD Detector:

• Parametric gain: 2.98, i.e 9.5dB of generated SQZ
• With SQB1 RR:
  • 8.7 dB of ASQZ, cc phi = 0.9 rad, 4MHz_mag=8.6mV
  • 5.9 dB of ASQZ, cc phi = 2.15 rad, 4MHz_mag=2.99mV 
• With FCIM:
  • 8.6 dB of ASQZ, cc phi = 0.65 rad,
  • 5.45 dB of ASQZ, cc phi = 1.9 rad

Henning did the switch between BAB and SQZ at 19:53 UTC

The parametric gain is 2.61, i.e. 8.3 dB of SQZ generated.

With the HD we measured 3 dB of SQZ and 6.5dB of ASQZ

The shot noise spectrum was full of peaks. We tried to improve it acting on HWP1 of EQB1 (EQB1 faraday HWP). We did not manage to improve the level

Then we tried to work on the CMRR of HD detector, and we found out that PD2 was sligthly misaligned.

After a fast tuning of HD PDs alignment we improved a lot the quality of HD spectra.

We reached at the end 8 dB of ASQZ and 5 dB of SQZ. Probably further tuning is needed

We left the retroreflector off and the system in FLT_IR_AA_FMODERR_TUNED

Our goal was to update the PyE873 software in order to satisfy the request of Computing Service for the code freezing. There were two thighs to do: prepare a cmt package and use conda instead of the env.sh script. The software manages piezo-electric motors inside the AEI squeezer source and it is available here Git pye873.

The activity started on Friday 11th morning. At the beginning we moved three processes with prefix SQZ_PI_stage from the generic machine olserver113 to the one dedicated for SQZ olserver149. The processes are:

SQZ_PI_stage_2f  - beam dumper
SQZ_PI_stage_pump  - beam dumper
SQZ_PI_stage_Homodyne  - mirror

During the test the laser light was present on EQB1_HD_CAM_FF, EQB1_HD_CAM_NF and EQB2_IR_Cam for reference in case the stages moved during the activity on the software.

Only the SQZ_PI_stage_Homodyne PI stage was monitored since it controls the position of a mirror.

Record for software developers: internal servo of the PI E-873 is not stable: sometimes it moves back and forth the actuator which may cause vibrations. That's why the in-loop operation must be turned off when the mirror is parked.

The first installation of the packaged returned:

Using 'default' alias ['farmn1']
---
Installation on farmn1
---
Versions defined in '/olusers/pm_user/.config/virgo_pm_versions.txt':

  root:v5r34p051
  FFTW:v3r3p30
  VirgoPolicy:v2r6
  CSet:v2r16
  Cm:v8r12p5
  Cbf:v4r13
  Cfg:v8r06p2
  Fr:v8r34
  Fd:v8r27
  Frv:v4r31

No standard version tags found for pye873 in version control repository
Exit request sent.
Connection to farmn1 closed.

We encountered two problems:

One with the access to the drivers which we solved with the help of Computing Service. We killed the process of another user which caused problems. The SQZ_PI_stage processes in VPM remained off.

The second one is that pipython dependency is not available in the conda environment. We have sent a request for adding it into the new version of the env.

Due to the fact that pye873.py software could not connect to the drivers, the position monitoring with light was meaningless.

The work has been continued on Monday 14th.

The pye873 package has been modified and successfully installed (it still depends on the manually installed pipython dependency). Version v1r0, v1r1 and v1r2 were installed. The output log of the last installation is:

PmInstall pye873
To work in the /virgoStaging area please type your \"bawaj\" login password:
Using 'default' alias ['farmn1']
---
Installation on farmn1
---
Versions defined in '/olusers/pm_user/.config/virgo_pm_versions.txt':

  root:v5r34p051
  FFTW:v3r3p30
  VirgoPolicy:v2r6
  CSet:v2r16
  Cm:v8r12p5
  Cbf:v4r13
  Cfg:v8r06p2
  Fr:v8r34
  Fd:v8r27
  Frv:v4r31

-> pye873 v1r2 (to be installed in /virgoApp)
     Conda v2r1p0 is in /virgoApp
--------
pye873 checkout
--------
Cloning into 'v1r2'...
chgrp swmgr /virgoApp/pye873/v1r2
chgrp swmgr /virgoApp/pye873
--------
pye873 configuration
--------
Creating setup scripts.
Creating cleanup scripts.
--------
pye873 compilation
--------
#CMT---> Info: Execute action make => gmake bin=../Linux-x86_64-CL7/
#CMT---> (Makefile.header) Rebuilding ../Linux-x86_64-CL7/Linux-x86_64-CL7.make
#CMT---> (constituents.make) Rebuilding library links
#CMT---> (constituents.make) Building conda_exec.make
#CMT---> Info: Document conda_exec
#CMT---> Warning: Source file ../Linux-x86_64-CL7/bin/PyE873.py not found
#CMT---> (constituents.make) Starting conda_exec
/virgoApp/Conda/v2r1p0/scripts/generate_exec.sh: line 14: activate: No such file or directory
Using /virgo/conda/envs/cmt-conda-py39-20220317 conda environment
Creating /virgoApp/pye873/v1r2/Linux-x86_64-CL7/bin/PyE873-conda
#CMT---> (constituents.make) conda_exec done
#CMT---> all ok.
--------
Make built files read only
--------
chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7
chgrp swmgr /virgoApp/pye873/v1r2/cmt
chgrp swmgr /virgoApp/pye873/v1r2/cfg
chgrp swmgr /virgoApp/pye873/v1r2/src
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/.gitlab-ci.yml
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7-incomplete
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/README.md
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/.gitignore
chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7/bin
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7/constituents.make
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7/conda_exec.make
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7/Linux-x86_64-CL7.make
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7/setup.make
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7/make.in
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7/cmt_build_library_links.stamp
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7/conda_exec.in
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7/library_links.in
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/Linux-x86_64-CL7/bin/PyE873-conda
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/cmt/cleanup.sh
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/cmt/cleanup.csh
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/cmt/requirements
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/cmt/Makefile
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/cmt/setup.sh
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/cmt/setup.csh
chmod 0o444 chgrp swmgr /virgoApp/pye873/v1r2/cfg/PiPythonDriver.cfg
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/cfg/config.ini
chgrp swmgr /virgoApp/pye873/v1r2/src/lib
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/PyE873.py
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libpi_pi_gcs2.so
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libicui18n.so.30.0
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libpi_pi_gcs2.so.3.8.0
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libpi_gcs_translator.so.1.8.0
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libicudata.so.30.0
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libfbclient.so.2.5.3
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libib_util.so
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libpi_pi_gcs2-3.8.0.a
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libicuuc.so.30.0
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libfbembed.so.2.5.3
chmod 0o555 chgrp swmgr /virgoApp/pye873/v1r2/src/lib/libwxPIGraph3D.so.1.1.2
Exit request sent.
Connection to farmn1 closed.

Version v1r0 and v1r1 are not functional and should be removed. This action will be asked to the Computing.

We performed a test of the newly installed version on the SQZ_PI_stage_2f process. The other two SQZ_PI_stage processes are still running the not frozen version of the code.

Yesterday evening at 19:47 UTC Henning switched between BAB and SQZ.

This morning I did the following operations:

• realigning the HD Detector on EQB1 with the SQZ reflected  by the filter cavity
• checked the demodulation phase of the AA loop based on dither line, I increased the demod phase of M6 X and Y by 0.1 rad
• measurement of the parametric gain from the 4 MHz mag signal on HD detector. It was 2.4, i.e. 7.6 dB of generated squeezing (max mag=7.55 mV min mag = 3.10 mV). ASQZ measured 6.9 dB
• raised the retroreflector on SQB1 (+300000 steps)
• here the maximum of the magnitude was 7.7 mV and we measured 7.2 dB of ASQZ

I left the SQZ_MAIN automation in FLT_GR_AA_NOIR

In addition yesterday after the SQZ meeting we performed some scan of the BAB (acting on green AOM) and the SC (acting on SC PLL reference) around the filter cavity peak, in order to understand if we have some chance to resolve the ITF arm resonances during the shift of this evening. The used ramp has an amplitude of 600Hz and a period of 5s

• BAB Scan (Filter cavity locked with mirrors + laser) 2023-07-27-17h57m04-UTC    info vardaro      'MAIN PLL:Ramp On [Channel=0,Start Freq=80196690,Stop Freq=80197290,Period=5.0]' sent to EQB1_DDS_PLL (figure1)
• SC Scan (Filter cavity locked with mirrors + laser)    2023-07-27-18h34m48-UTC    info vardaro      'SC PLL:Ramp On [Channel=2,Start Freq=100093941,Stop Freq=100094541,Period=5.0]' sent to EQB1_DDS_PLL (figure2)
• SC Scan (Filter cavity locked only with mirrors)        2023-07-27-18h45m13-UTC    info vardaro      'SC PLL:Ramp On [Channel=2,Start Freq=100093941,Stop Freq=100094541,Period=5.0]' sent to EQB1_DDS_PLL (figure3)

In order to prepare the SQZ shift of friday 2n june we switched the squeezer in SQZ mode.

We religned the HD from input mirror and we found:

• SQZ 5.2dB @2rad
• ASQZ 8.3 dB @ 0.5 rad 
• Parametric gain 2.72 i.e 8.7 dB of generated squeezing

Then we rised the retroreflector that was completely misaligned after the work of the last week. We raised it by moving it 370000 steps in Y direction. We realigned it using cameras (at the beginning the SC did not arrive on cameras so we searched it blidly:

• we moved retroreflector H by 875 steps
• we moved retroreflector V by 6700 steps

after that we found 

• 5.5 dB of SQZ @ 2.2 rad
• 8.5 dB of ASQZ @ 0.85 rad
• parametric gain 2.8 i.e 8.9dB of generated squeezing

Just before rising the retroreflector we had 8.4mV of 4MHz mag (FCIM) and just after 8.6mV.,this is compatible with the 4 % of propagation losses that we mesasured in the past.

We left with SQZ angle tha automation SQZ_MAIN in FLT_GR_AA with the line that opens the SC shutter commented (configuring green of SQZ_FLT)

Squeezer translational stages

during the squeezer alignment we have experienced communication errors between the PI_stage processes and the actuators. AEI team used the PI GUI under Windows virtual machine for the alignment.

We will take the opportunity for the debug and migration of the PI_stage process. Luca agreed to lead the migration process.

Any test involving the squeezer actuators  should be discussed with the AEI team. Before a test which risks to move randomly the actuators, all lasers must be shut down to avoid sweeping laser beams randomly over components inside the box.

MZ realignment:

       This morning we proceeded with the realignment of  the squeezer pump power MZ stabilizer   as  did one year ago (#https://logbook.virgo-gw.eu/virgo/?r=56246) and the OPO tining.

       The starting state for MZ was with a contratrast from  ~0.7 Vp-p to ~ 1.6 Vp-p around the mean value of 1.2 (see attached plot).

We acted again on the same actuator (see pictures in

OPA tuning

        Then we proceeded with the OPA. In this case, maybe due to the humidity state,we were not able to improuve the alignemnt. We decide to leave the system as it is and wait for the humidity (more) and temperature observaton in the next two weeks  to eventually act again. (Only the screws on the last steering before the OPA were moved - see picture in #https://logbook.virgo-gw.eu/virgo/?r=56246 )

Rough extimation comparing the peak to peak power:

• OPA misalignment: ~ 7%
• OPA mismatch: ~ 1%

P.S:: Before to start a problem on the remote control of the squeezer translational stages was solved (a dedicate report will follow)

The recovery of QNR system after the electrical blackout was performed on Thursday 18 May and Monday 22.

The following electronic was reswitched on:

1. Squeezer Main Laser, Squeezer CC Laser and EQB1 Subcarrier Laser
2. The 4 DDS box on the rack 5 (restarted off-on to update the IP address): g25squeeze4, g25squeeeze5, g25squeeze5 and g25squeeze7
3. The EQB1, EDB and EQB2 QPDs were restarted, both the BIAS and the Power supply
4. The 80MHz generator for the phase camera+PLL AOM was restarded via g25squeeze2 DAQ BOX
5. The 80 MHz generator used for the Main PLL was re switched on with the following parameters:
   • Frequency 80 MHz
   •  Amplitude 0 dBm
   • Frequency modulation External
   • Frequency modulation DC
   • Frequency modulation slope 44 kHz
6. The 78 MHz generator used for FMODERR loop was restored with the following parameters:
   • Frequency 78.919655  MHz
   • Amplitude pk-pk 0.9V
   • Modulation FM
   • Tuning range 600 Hz
   • Remember to switch on the output and the modulation (both the led below buttons should be on)

Part 1 - The suspended benches and mirrors are controlled again:

On thursday 18 the first action performed was the control of SQB1, SQB2, FCIM, FCEM

• SQB1:
  • we checked in the VIM the position of the DOF and we found that the setpoint in the config file were not updated in particular LC_X -3700 (last position) and LC_Y -550 (last position), we saved in the config file LC_X and we updated online LC_Y (still not saved)
  • we opened the tracking loop (SDB1 was uncontrolled)
  • we closed the angular controls
  • we closed the position controls
• SQB2: 
  • position are checked and are ok
  • we opened the tracking loops
  • closed the angular controls
  • closed te position controls
• FCIM, FCEM: 
  • with a trend we found the last position of FCIM and FCEM MAR_TX and MAR_TY when the cavity was aligned and we set it online
  • we closed the Local controls MAR_TX, MAR_TY and MAR_TZ
  • we closed the position controls of the inverted pendulum

On Monday 22 May we closed again the tracking loops of SQB1 (once SDB1 was controlled) and SQB2 once (NI was controlled). We aligned also the filter cavity maximizing the flashes in transmission.

In the meantime Henning rechecked the squeezer and the BAB was restored. A problem on SQZ Translation stages occured we could not move them anymore (up to now we can not switch from BAB to SQZ)

Part 2 - Recovery of PLLs

• Until the recovery of the INJ system we could only try to lock the CC and SC PLLs:
  • CC PLL: once restarted the CC laser it worked at the first attempt (SQZ_MAIN in LOCKED_PLL_CC _STAND_ALONE)
  • SC PLL: was not working thus we realized that the hardware was still off. Once we also switched off-on the noise eater 2 times and we could lock the PLL at the first attempt
  • MAIN PLL: once the RFC was locked we performed the following actions
    • Try to lock the PLL without succes
    • With the MUX out we checked the value of LO and RF input (looking the EQB1_MAIN_PLL_STATUS). For the LO we had a good signal for RF no. 
    • We disconnected the LO cable and we realized that was the generator. So RF cable is the beat note this means that the beat note was not present
    • We checked the Photodiode EQB1_MAIN_PLL_PD1_DC and PD2_PDC and we realized that a part of the power was missing probably the pick-off of the inj laser
    • ALS was present thus the beam in the fiber was present, thus after some investigation and with the help of Mattieu we realized that probaby the RF generator of the PLL+Phase camera AOM was not restored
    • I reconfigured the channel 1 of the g25squeeze2 DDS at 80 MHz 
    • After that we regained the missing power on the MAIN_PLL_PD1_DC and PD2_DC and the PLL locked at the first attempt

Part 3 recovery of the filter cavity

• Once the three PLLs were locked again we realigned the filter cavity and we relocked it. A huge noise was present thus we forced in the SQZ_CC_Ctrl process the filter0, the FC_Error signal based on GR_PD 
• The Filter cavity relocked but once we engaged the AA the filter cavity misaligned
• After some investigations we realized that no power on EQB1 QPDs was present. Thus we asked to Fabio to check if the QPDs were on after the ENEL Failure. He reswitched on all the QPDs and the AA worked again
• We put a Scan on PLL SC and we unlocked and relocked the cavity until we found SC flashes in transmission
• We maximized the SC flashes in transmission closing the PY_SQZ_IR loop using SC_PLL as actuator
• We closed IR_AA loop
• We manually closed the FMODERR loop and helping it putting a DC offset od 3.2V then we removed it with a120s ramp
• We performed FMODERR and we reached the state FLT_IR_AA_FMODERR_TUNED. We set 0 Hz detuning in SQZ_FLT.ini for FMODERR
• We religned SC into OPA using the SC AA loop
• We maximized the tranmission of the SC into OPA using M21 and M22 with the IR AA closed. We reached again 14.7V of IR transmission BAB+ SC, i.e. 13.6 V of SC and 1.1V of BAB
• We left for the night the filer cavity in loked IR_AA FMODERR_TUNED

Still to do:

• Update the setpoint of SQB1 MIRROR1 and 2 after the blackout
• Update the demodulation phases of SQB1 AA loop with ITF
• Realign the HD detector with SQZ beam
• The reflected beam from FLT seems clipped on EQB1 cam, to be checked
• The SQZ translation stages are still not working

In fig 4 of the entry the GPS of SQZ spectrum was wrong. Here the correct plot

This report is about the afternoon shift of Sunday 23/04

Goals of the shift:

• Inject quantum states in the ITF, close CC and AA loop. Measure SQZ, ASQZ and perform a CC loop phase scan
• Inject the BAB in the IT and try to estimate the ITF losses.

0. Preparation of the shift

We found the ITF locked in Low Noise 1 at the beginning of the shift with a BNS range higher than 20 Mpc. We tried to open th SDB1 shutter moving it 10000 steps with spead 5. We could move it 30000 steps, the shutter was not completely opened and the ITF unlocked.

We profit of the ITF DOWN to switch on the IR light of the camera ipcam43, then we open the shutter and we asked Andrea to relock the interferometer.

Once the ITF relocked we found out that the SDB2_B1_4MHz was about 0.1mW i.e. 1/20 of the mag of the last shift. This means that we did not tuned well the SQB1_HWP2 to send all the SQZ beam toward the HD detecor (after fiday shift)

We took the following data:

• 15:13:00 UTC: SDB2 FI Shutter Open, EQB1_IR Shutter Open, SQB2_HWP2 not well optimized
• 15:15:13 UTC: SDB2 FI Shutter Open, EQB1_IR Shutter Closed (measurement ended at 15:18:00 UTC)
• 15:22:00 UTC: SDB2 FI Shutter Open, EQB1_IR Shutter Open, SQB2_HWP2 optimized
• 15:28:00 UTC: the SQB1_HWP2 was rotated to inject SQZ toward ITF

After the optimization of the HWP  the SQZ beam was sent toward EQB1 HD detector. The remaining magnitude on SDB2_B1_4MHz signal was 5uV. 

1. Injection of quantum states into the ITF

Once all the HWP were tuned we started to send Quantum states into the ITF. We closed the CC loop and the AA loop with OMC 

• 15:46:00 UTC with the loop closed we selected the CC phase that maximize the SDB2_B1_4MHz_mag sigal. CC phase -0.33 rad, mag = 2.15 mV. We noticed a peak at 1887 Hz in B1, DARM and Hrec that was higher than before.
• 16:02:26 UTC we swithced on a dither line at 2200 Hz in the CC loop driving with an amplitude o 0.3mV. This lines is used for the implementation of the Slow CC loop as was performed in O3. This lines is visible on {SQZ,SDB2}_B1_4MHz_mag and in SQZ_CC_Corr error signal.
• 16:11:19 UTC we performed a phase scan of the CC phase from -0.33 rad to 3.14 rad in 600s. From the phase scan (fig1) we extracted the SQZ angle 1 rad and ASQZ angle 2.7 rad 
• 16:46:02 UTC shot noise measurement i.e. EQB1_IR_Shutter closed 
• 17:00:00 UTC ASQZ injection in the ITF. CC phase 2.7 rad
• 17:04:20 UTC SQZ injection in the ITF CC phase 1 rad
• 17:10:00 UTC to 17:50:00 UTC  we left the CC open and we observed the magnitude evolution to see if the alignment drifts during the time. The alignment was very stable. (fig 5)

In fig2,3,4 you can see the SQZ ASQZ Shot noise in time domain and in spoectra. We measue 1 dB of SQZ and 3.5 dB of ASQZ. The parametric gain was 2.68 and we expected 8.6 dB of generated Squeezing. Thus the alignment of the system was better than last week end. (Sunday 16 Apr)

2. Characterization of the ITF losses with the Bright alignment beam

 In the second part of the shift we wanted to inject the BAB into the ITF, detune it in frequency and measure the beat note between the BAB and the ITF main beam at different frequencies. From these data we will try to extract some information about the ITF+SR losses.

• 18:03:00 UTC Henning switched from SQZ to BAB
• Looking the EQB1_HD_DIFF_AUDIO channel we tuned the CC Loop Dac_offset to detune in frequency the SQZ Main Laser with respect to the ITF Laser. With a DAC offset of 0.2V we had a detuining of 4592 Hz

Then we wanted do decrease the power of the BAB. We know that the BAB power is 2 mW and that the power on B1_DC is 8mW. We tried to inject 80 uW of BAB in the ITF. We want to reduce the power of the BAB by a factor 25.

We did the fllowing operations:

1. inserted the DL
2. We put HD MIR in the HD beam path to send the beam toward EQB1_IR_PD_MONI and EQB1_Cams
3. we remove the HD Filter 
4. We switched off the LO
5. We measures the power of the BAB on EQB1_HD_PD1_DC 0.714V 
6. We mwasured the power od the BAB on EQB1_IR_PD_MONI 3.284V
7. We rotated the EQB1_FI_HWP1 until the power of the two Photodiodes decresed by a factor 25: 0.312V for IR_PD_MONI and 0.0286 V for PD1 (18:29:30 UTC)

@18:29:30 UTC We removed the Delay line and we injected 80uW of BAB into the ITF, The effect on the ITF was too high: different order of magnitude, thus we decided to further reduce its power.

@18:30:00 UTC we removed again the Delay Line. This time the BAB power was reduced by a factor 250. The power on IR_PD_MONI was 0.013V and the one on HD_PD1 was 0.0029 V. The height of the beat note in DARM was still too high. We decide to futher decrease the power

@18:52:34 we removed the Delay line with the minimum power that we could reach. The power of the BAB was reduced by a factor 7298 and the and the power on IR_PD_MONI was 0.45 mV. Thus we are injecting about 0.3 uW of BAB into the ITF

Test of the linearity@ 4592 Hz:

The values in the second column are not exacly the double one wrt the other (we are not considering the floor of the photodiode that should be -1e-4V) to be checked

Measurement of the transfer function (BAB on IR PD MONI 0.45mV)

At 19:45 UTC the ITF unlocked. We put the delay line to not send anything to the ITF

At 20:21 the ITF relocked and the sensitivity was again stable at 20:28 UTC.

At 20:29 we removed the DL. Immedately unlocked

For both the unlock Andrea found the SR misaligned by more than 10urad. We realized that the beat note due to the BAB in DARM  (486Hz) was very near in frequency to the High Frequecy dither line of DARM at 491 Hz. This line is used to align the SR thus we spoiled the ITF alignment.

We will avoid this in the next attempt

At 20:39:53 UTC we closed the SDB1 FI shutter

At 20:45 We rotated the EQB1 HWP. Henning switched agian in SQZ Mode, we realigned the DL and we retuned back the SQB1 HWP2.