Reports of 45019
Detector Operation (Operations Report)
amagazzu - 18:06 Monday 26 October 2020 (49746) Print this report
Operator Report - Daily shift

The shift was dedicated to the reinstallation of the Squeezer Box ( see entry #49745 ) and Green beam alignment on West arm cavity ( carried out by Tacca and Leroy ). To allow this last activity a lock of the West cavity was required; luckily the alignment was still good after the weekend and we were able to lock it at the first attempt.
The SQZ and ALS activities continued during the afternoon. ALS alignment still in progress.

DET
At 13:45 UTC the ID loops of SDB1 were opened by the Guardian. I tried to close them, but this action seems to excite the Local control of the bench. Thanks to V. Boschi the loops were restored at 15:05 UTC.

SBE
During the weekend the SPRB Vertical correction decreased below the safe threshold. From around 8:40 UTC to 8:55 UTC, using the related motors, I returned the value around zero.

AdV-AEI Squeezer Integration (AEI squeezer works)
Vahlbruch, Mehmet, Vardaro, Sorrentino - 15:19 Monday 26 October 2020 (49745) Print this report
Reinstallation of AEI Squeezer
The reinstallation of the squeezer box is finished and the following modifications have been made:

1.) A 532nm output port was added with an intensity of 27mW.
2.) Additional to the already existing 1064nm output for the PLL, we added another port with an intensity of 2.5mW.
3.) One translation stage with an HR Mirror was moved closer to the OPA cavity, thereby bypassing the on-board Faraday Isolator. This mirror sends the OPA output field through another new output port. Depending on the operation mode this new output port provides now either the bright alignment beam (1.3mW) or the squeezed vacuum field.
4.) The coherent control frequency was shifted from 7MHz, as used in O3, to now 4MHz. The according on-board photodiode has been replaced.

We measured squeezing with the on-board homodyne detector (Visibility=98.5%).
Due to OPA crystal degradation, the intra cavity losses are increased and the squeezing level is currently limited to approximately 5dB (7.5dB anti-squeezing).
We will prepare a replacement OPA in Hannover. At this squeezing level we could not observe a difference between using the 7MHz or 4MHz coherent control frequency.

With the settings as used in O3, we observed that the coherent control laser was running multi-mode very strongly. Both modes had roughly the same intensity.
We moved the laser crystal temperature up a little bit (31.09 -> 31.40), which solved this problem. As a consequence the main squeezer laser is pretty close to multi-mode operation. Once the external PLL is installed this needs to be further investigated to find more stable operation points.
Images attached to this report
AdV-SVS (Installation)
montanari, vardaro, gherardini, nenci, sorrentino - 13:06 Monday 26 October 2020 (49744) Print this report
Comment to ESQB1 cabling (49714)

The cabling between DET lab and DET electronic room continued over Thursday and Friday. Now the cabling of AEI squeezer and SQB1 multiSAS are completed. We also added the cables for environmental sensing on ESQB1. Cables for the remaining ESQB1 hardware will be completed after the end of the works on AEI squeezer.

Images attached to this comment
Detector Operation (Operations Report)
amagazzu - 9:15 Monday 26 October 2020 (49742) Print this report
Operator Report - Initial Status

State of Virgo: Unlocked.
ITF Mode: Upgrading.
Quick Summary: IMC locked; SNEB in-air, SDB2 loops open; all suspensions loops closed; SR-BS Valve close; TCS CO2 lasers off; INJ_MAIN in pause, all the other automation nodes OFF.
Activities ongoing since this morning: No activity known so far in the control room.

AdV-SBE (MultiSAS controls)
bertolini - 19:36 Sunday 25 October 2020 (49741) Print this report
SWEB suspension re-balanced
I have rebalanced the SWEB suspension to offload the actuators. Thermal drift is still ongoing since SWEB was put back in vacuum last Friday (See plot). To be checked tomorrow morning before starting ALS activities. Two remarks: 1. a sizeable static torque in Ty seems to be present at the level of the bench stage, 2. a 400 mHz persistent oscillation (with ~20 um pp) is visible in both X and Z directions which couples also to Tz and Tx.
To be investigated.
Images attached to this report
On-site interventions (Site Infrastructure - Conditioning)
soldani - 15:17 Saturday 24 October 2020 (49740) Print this report
AHU for INJ and DET Lab restarted
This morning, aroun 12,15 (local time) due to a storm, the Enel went out and the generators started working;
like other times, it happened that, due to the switch from enel to generators, the supply fans of the AHU for INJ and DET stopped.
This is because (known problem) having to respect a fixed frequency, the respective inverters are in manual mode.
At about 2.30 pm (L.T.) I reached the site to restart them both.

All flags on DMS about INJ and DET are gray, even if I restarted the installations: I think servers has to be restarted too....
AdV-SVS (Installation)
vahlbruch, mehmet, sorrentino - 0:49 Saturday 24 October 2020 (49739) Print this report
AEI squeezer on ESQB1

The AEI squeezer was installed on the ESQB1 table in the afternoon. Set up will continue over the weekend.

Images attached to this report
AdV-ALS (End arm injection)
tacca - 23:25 Friday 23 October 2020 (49738) Print this report
Comment to Green beam alignment on west arm cavity (49725)
In the afternoon the West arm cavity was relocked with the IR beam.
In order to look for green flashes, we decided to try the same method used with SWEB in air. Therefore, we started to move Maux1 and Md to change the entry point of the green beam in the West cavity checking the centering on M3 and the beam back-reflected on EWEB. Many different combinations of Maux1 and Md have been tried but we did not succeed in superimposing the axis of the green propagation with the axis of the locked cavity. Finally, we tried to slightly move also the SWEB angular working points, keeping the cavity locked with the IR and compensating the motion using Md, still without success.
The work will continue next Monday, possible different approaches:
- lock the West arm on B4 and induce larger angular movements on SWEB;
- make a narrower snail with Maux1 and Md;
- set the Galvos back on the working points used in air and move Maux1 and Md.
AdV-AEI Squeezer Integration (General)
mehmet, vahlbruch, vardaro - 19:45 Friday 23 October 2020 (49737) Print this report
AEI Squeezer laser are on again in the DET cleanroom

Today we switched on again the AEI squeezer laser in the DET Lab, in particular in the new FDS cleanroom inside the DET clean room.

From today remember to wear safety goggles when entering in the clean room

Detector Operation (Operations Report)
chiummo - 18:10 Friday 23 October 2020 (49736) Print this report
Comment to Operator Report - Daily shift (49728)

Taking advantage of the accident to PR control, I resetted the thermal correction to the master laser which had been quite high in the past days. INJ was relocked afterward.

Images attached to this comment
Detector Operation (Operations Report)
Gherardini - 18:01 Friday 23 October 2020 (49728) Print this report
Operator Report - Daily shift

Below the list of the today's activities:

- squeezer board re-installation & cabling (in progress);
- green beam alignment on west arm cavity by Matteo, Raffaele and Romain (in progress);

SUSP

at 9:10UTC the PR local control get crazy and the F7 controls opened by the guardian because of one of the two SLED has switched off, probably due to some human activity around the tower base; with the help of Paolo from remote the SLED had been switched on and the control restored.

Comments to this report:
chiummo - 18:10 Friday 23 October 2020 (49736) Print this report

Taking advantage of the accident to PR control, I resetted the thermal correction to the master laser which had been quite high in the past days. INJ was relocked afterward.

Images attached to this comment
AdV-SVS (Installation)
vardaro, zendri - 16:44 Friday 23 October 2020 (49735) Print this report
SVS electronic partially installed on the racks

We started to populate the rack5 and the FDS-Rack2

Rack5 from the top (figure 1 rack on the left)

  • DAQ BOX 58 (2U)
  • Cable duct (1U)
  • Wenzel 500 Mhz (1U)
  • 4 DDS Boards (1 each)
  • PLL Board (1U)
  • 3x Line Drivers/ Line Receivers (1U each)

Missing on rack 5: 2x DCF and DCG (12U total), 1 or 2 cable trays and 2 Line Driver/Receiver Box

Rack FDS2 from the top (figure1 rack on the right):

  • DAQ BOX 91 (2U)
  • Cable Duct (2U)
  • DAQ BOX 90 (2U)
  • Cable Duct (2U)
  • DAQ BOX 89 (2U)
  • Cable Duct (2U)
  • 2 Translation Stages and 2 Tip Tilt Driver
  • Empty space
  • QPD Controller SN 30 (2U)
  • QPD Controller SN 23 (2U)
  • Rohde & Schwartz Power Supply (3U)
  • Rohde & Schwartz Power Supply (3U)

Missing on FDS Rack 2: 2 x 5U Boxes with 6 PI Controller each one

Images attached to this report
AdV-SVS (Installation)
vardaro, zendri - 15:57 Friday 23 October 2020 (49734) Print this report
RF electronic for the AEI squeezer

Today we recabled all the RF cables to the DDS1 (g25squeeze1)

  • channel 1 PDH @ 128.53 MHz
  • channel 2 Int PLL ref frequency @ 7MHz
  • channel 3 Homodyne detector demodulation @ 7MHz
  • channel 4 Pump Phase demodulation @ 14 MHz

The variable output of the channel 1 is connected to the mDemod channel 3 DAQ BOX 58

We also connected the 80MHz reference for the PLL Ext to the channel 1 of the DDS2 board (g25squeeze2)

 

Then we reconfigured the two DDS boards and we connected them to the 500MHz OCXO.

Finally we cabled and switched on the PLL Boards (the Beat Note of the PLL Ext is now the cable Spare2 N 56

To control again the PLL we had to restart the SQZ istance of the tango server on the phasecam1 pc. We found it switched off, we switched on it again and then we run again the tango starter with the following commands

DataBaseds 2 -ORBendPoint giop:tcp::20000 &

export TANGO_HOST=olserver129:10000

Starter phasecam1 &

When the two PLL boards were reacheble we set the same laser temperature used for the O3 run:

  • Ext PLL OUT SLOW: 38110
  • Int PLL OUT SLOW: 37720
Images attached to this report
AdV-PSL (Commissioning of SS)
mwas - 14:27 Friday 23 October 2020 (49733) Print this report
Comment to Recurrent increase in PSL noise also present without IMC (49705)

For the data between Oct 13 and 14, looking at INJ_EOM_CORR is not a good witness channel. The input mode cleaner was unlocked (on purpose) and there was no correction sent to the EOM. For that night a good channel to look at instead is PSL_PMC_REFL_I_FS_rms.
 

Environmental Monitoring (Environmental Monitoring)
rderosa - 13:32 Friday 23 October 2020 (49731) Print this report
Test of Single Axis Episensor on DET tower

This morning, by taking advantage of the cabling activities between DET lab and DER, I was able to mount and test two single axis episensor on the east (photo 1) and north (photo 2) flange of the DET tower. I used the channels already available for the episensor installed on the SQZ bench (currently disconnected), so the sensor on the east flange is ENV_SQZ_SEIS_x while the sensor on the north flange is ENV_SQZ_SEIZ_Y.

The two probes work fine: a little adjustment of the offset has to be done. Since on the east flange we already have a PZT accelerometer (ENV_DT_ACC_Z) and there is another PZT at the end of the pipe located on the north flange (ENV_SQZ_PIPE_ACC_Y), it is also possible th have a comparison (fig 1).

Since the second episensor is on the flange, measuring along Z, while the second PZT accelerometer is on the pipe, measuring along Z, the coherence between these probes is limited (also the spectra are clearly different...).

After the test the signal of the two episensors were disconnected, so no signal is available now.

Images attached to this report
AdV-ALS (End arm injection)
bonnand, flaminio, tacca - 13:05 Friday 23 October 2020 (49732) Print this report
Comment to Green beam alignment on west arm cavity (49725)
This morning we went to the CEB to look for the green beam on WI, BS, PR and SIB1 by eye.

We can see the green beam on the WI but the light is scattered by the metal on the back of the mirror (according to Ilaria that is part of the ring heater).
Moving the green beam we can see more or less light.
Moving the green beam on the right of SWEB_M3 seems to move the beam on the WI mirror towards the right.
In this condition some green light is visible also on the edge of the baffle in front of the WI.
See picture.

On the BS we could not find any useful window to look at the mirror (maybe we should have a better look).

On the SIB1 we found a window on the north-west-low side.
From there it is possible to see the baffle placed on the ground in front of SIB1 (but it is very difficult since the angle of view is very large).
Maybe one could try to put a camera there.

On PR we found a very well placed window on the north-west-up side.
We mount a camera there.
We took the camera from the north-east-up side of the detection tower.
This is security camera so we are not sure about its sensitivity.
We placed it so to see the front face of the PR mirror.
We use this camera to look for the green beam on the PR payload while moving the dichroic mirror.
We could not see the green beam on it (while, as usual we saw it on the WI mirror).
Images attached to this comment
AdV-PSL (Commissioning of SS)
direnzo, narnaud - 11:40 Friday 23 October 2020 (49729) Print this report
Comment to Recurrent increase in PSL noise also present without IMC (49705)

Triggered by Nicolas, I've run NonNA-corre to estimate the Pearson cross-correlation coefficient between a target channel, in this case the max or the rms of INJ_EOM_CORR from the trend frame, and a set of (330+) channels from trend: [ENV_*,PSL_*,INJ_*], either *_rms or *_max. The results are then ranked on the base of (the absolute value of) this coefficient, and listed in at the links below:

Mind also the log files, with an extended list of most correlated channels.

Of course most/some correlations are trivial and expected (like the one with INJ_IMC_REFL, which however I didn't exclude from the analysis as a check) but hopefully something could be of interest. Also, feel free to post comments/requests or to suggest me other similar analyses.

AdV-PSL (Laser Bench setup)
direnzo, narnaud - 11:34 Friday 23 October 2020 (49730) Print this report
Comment to Beam dump on the slave laser (49676)

Triggered by Nicolas, I've run NonNA-corre to estimate the Pearson cross-correlation coefficient between a target channel, in this case the max or the rms of INJ_EOM_CORR from the trend frame, and a set of (330+) channels from trend: [ENV_*,PSL_*,INJ_*], either *_rms or *_max. The results are then ranked on the base of (the absolute value of) this coefficient, and listed in at the links below:

Mind also the log files, with an extended list of most correlated channels.

Of course most/some correlations are trivial and expected (like the one with INJ_IMC_REFL, which however I didn't exclude from the analysis as a check) but hopefully something could be of interest. Also, feel free to post comments/requests or to suggest me other similar analyses.

AdV-ALS (End arm injection)
bonnand, flaminio, tacca - 9:56 Friday 23 October 2020 (49727) Print this report
Comment to Green beam alignment on west arm cavity (49725)
We went to the DAQ room to check the laser that we are using for the producing the green beams.
It is a Koheras BoostiK Y10 from NKT Photonics.
According to the data sheet the line-width is <20 kHz.
AdV-ALS (End arm injection)
bonnand, flaminio, tacca - 9:53 Friday 23 October 2020 (49725) Print this report
Green beam alignment on west arm cavity
Yesterday we continued to work on the alignment of the green beam on the west arm.

After lunch SWEB was suspended and under control in vacuum (thank you Alessandro).
The motion of the bench in Tx and Tz was larger than usual (+/- 2 urad).
The control gain was tuned improving a little bit the situation but the motion remained larger than usual.

The bench position was adjusted to allow the IR beam to reach the photodiode.
The west arm cavity was locked.

We then align the green beam using Galvo1 and Galvo2 in order to:
1. Center the green beam on M3.
2. Have the beam retro-reflected on the camera on the Aux bench (= auto-collimation).
In this situation we could see the green beam on WI and some green light on WE but no trace of flashes.

We went to the WE building to check if the auto-collimation was still good.
We looked on the diaphragm placed before the fiber collimator.
Indeed, the autocollimation was still good (no need to tune anything).

We then move the galvos to see if we could move the beam on the WI input.
The motion that we can see on the WI is very small.
Very rapidly the beam disappears because it clips on the SWEB mirrors.
It seems that the galvos are unable to produce large motions of the beam on the WI.
Maybe they can be used only when the alignment is close to the optimal.

We then try to move the bench a little bit (anyway we cannot move it too much if we want to keep the lock).
and adjust the beam on the bench with the galvos.
The result is similar to the one obtained before when we moved the galvos only.

We put back everything close to the optimal position (autocollimation and beam centered on the M3 mirror).
We unlocked the west arm cavity.
We start moving WI and WE in order to align the cavity on the green beam axis.
Depending on the WI and WE mirror positions we could see bright spots on both the WI and WE mirrors.
On the WE mirror the beam has a kind of "comma" (,) shape (also visible on the WI but much less).
It seems that by moving the WI and WE mirrors we can achieve a strange cavity resonance with no flashes.
We asked ourselves if the line-width of the laser that we are using is small enough to see cavity flashes (our cavity has a 50 kHz FSR).
We will have to check this.

Then, thanks to Ilaria and Maria, we had dinner (respecting social distance, of course)
A very useful support.

We then put everything back to the "optimal position" (auto-collimation and M2 mirror centered) and lock again the west arm cavity.
Putting the mirrors back to the positions that they had during the previous lock was particularly painful because the suspension control GUI is not working well (TANGO-SAT issues) and the standard procedure is not straightforward.

From there we started moving the dichroic mirror on SWEB using the pico-motors (we did not move the Aux mirror on SWEB).
Using the dichroic mirror it was possible to move the beam on the WI mirror much more clearly than with the galvos.
We wanted to see if the beam reaches the BS but there is no camera looking to the BS.
We wanted to see if the beam reaches the reflective faces of the PR mirror but there is no camera looking at the reflective face of the PR mirror.
We wanted to see if the beam reaches the diaphragm placed on SIB1 but there is no camera looking at the diaphragm placed on SIB1.

23h30: time to go home.
Comments to this report:
bonnand, flaminio, tacca - 9:56 Friday 23 October 2020 (49727) Print this report
We went to the DAQ room to check the laser that we are using for the producing the green beams.
It is a Koheras BoostiK Y10 from NKT Photonics.
According to the data sheet the line-width is <20 kHz.
bonnand, flaminio, tacca - 13:05 Friday 23 October 2020 (49732) Print this report
This morning we went to the CEB to look for the green beam on WI, BS, PR and SIB1 by eye.

We can see the green beam on the WI but the light is scattered by the metal on the back of the mirror (according to Ilaria that is part of the ring heater).
Moving the green beam we can see more or less light.
Moving the green beam on the right of SWEB_M3 seems to move the beam on the WI mirror towards the right.
In this condition some green light is visible also on the edge of the baffle in front of the WI.
See picture.

On the BS we could not find any useful window to look at the mirror (maybe we should have a better look).

On the SIB1 we found a window on the north-west-low side.
From there it is possible to see the baffle placed on the ground in front of SIB1 (but it is very difficult since the angle of view is very large).
Maybe one could try to put a camera there.

On PR we found a very well placed window on the north-west-up side.
We mount a camera there.
We took the camera from the north-east-up side of the detection tower.
This is security camera so we are not sure about its sensitivity.
We placed it so to see the front face of the PR mirror.
We use this camera to look for the green beam on the PR payload while moving the dichroic mirror.
We could not see the green beam on it (while, as usual we saw it on the WI mirror).
Images attached to this comment
tacca - 23:25 Friday 23 October 2020 (49738) Print this report
In the afternoon the West arm cavity was relocked with the IR beam.
In order to look for green flashes, we decided to try the same method used with SWEB in air. Therefore, we started to move Maux1 and Md to change the entry point of the green beam in the West cavity checking the centering on M3 and the beam back-reflected on EWEB. Many different combinations of Maux1 and Md have been tried but we did not succeed in superimposing the axis of the green propagation with the axis of the locked cavity. Finally, we tried to slightly move also the SWEB angular working points, keeping the cavity locked with the IR and compensating the motion using Md, still without success.
The work will continue next Monday, possible different approaches:
- lock the West arm on B4 and induce larger angular movements on SWEB;
- make a narrower snail with Maux1 and Md;
- set the Galvos back on the working points used in air and move Maux1 and Md.
Detector Operation (Operations Report)
Gherardini - 8:49 Friday 23 October 2020 (49726) Print this report
Operator Report - initial status
State of Virgo: Unlocked.

ITF Mode: Upgrading.

Quick Summary: IMC locked; SNEB in-air, SDB2 loops open; all suspensions loops closed; SR-BS Valve close; TCS CO2 lasers off; INJ_MAIN in pause, all the other automation nodes OFF.

Activities ongoing since this morning: no activity known so far in the control room.
Images attached to this report
AdV-ISC (Commissioning up to first full interferometer lock)
vardaro - 20:31 Thursday 22 October 2020 (49724) Print this report
Guide for the locking of the North and West Arms

Here below the instructions for the cavities locking

Preliminary steps

  • Open a terminal
  • go in the folder wich contains the two scripts by typing: "cd /olusers/virgorun/ISC/LSC"
  • start ipython

Run of the locking scripts

  • for the North Arm type "run narm _lock.py"
  • for the West Arm type "run warm_lock.py"

Then you acces to the following functions:

  • {N or W}ARMlock() to lock the arm
  • {N or W}ARMunlock() to unlock the arm
  • {N or W}ARMdrift_ctrl(1) to switch on the drift control
  • {N or W}ARMdrift_ctrl(0) to switch off the drift control
  • {N or W}ARMhandoffB4() to pass from the lock in transmission to the lock in reflection

To lock the cavity in transmission:

  1. {N or W}ARMlock()
  2. {N or W}ARMdrift_ctrl(1)

To pass from the lock in trasmission to the lock in reflection

  1. {N or W}ARMhandoffB4() with the cavity locked in trnsmission

To unlock the cavity (either from the lock in transmission or reflection)

  1. {N or W}ARMunlock()

Note that: to simplify the things today I renamed the functions in order to be coherent between the two arms. I tested only the script of the North arm, I could not test the script for the west arm because there was an ALS acrivity

Detector Operation (Operations Report)
berni - 18:00 Thursday 22 October 2020 (49723) Print this report
Operator Report - Daily shift

Below the list of the activities communicated in control room:

- SQZ cabling inside the detection lab (in progress);

 - ALS alignment by Matteo, Raffaele and Romain (in progress);

- mechanical works around SQZ area by LAPP team (in progress);

AdV-TCS (CO2 laser projector)
nardecchia - 16:46 Thursday 22 October 2020 (49722) Print this report
Temporary cover for the WI CO2 CH bench

Today, I covered the WI CH CO2 bench with a pellicle layer as a temporary solution to protect the optics from the dust.

The final plexiglass cover will be installed in a few weeks.

Images attached to this report
AdV-PSL (Pre-mode-cleaner block)
cleva - 16:04 Thursday 22 October 2020 (49721) Print this report
PMC - 9 kHz oscillation raising

it seems the unlock of PSL/IMC has been triggered by the mechanical resonnance of the PMC piezo.

Plot 1 PMCREF_I features a quiet period then a noisy period which ends with a large glitch which causes the unlock.

plot 3 is a zoom which shows a preliminary glitch before the large one

plot 2 is a zoom of the preliminary glitch:

we see the EOM_CORR is ~ 0,2 Vpp, that is 120 Vpp on the crystal (the PA83 amplifier which drives the crystal is limited to 120 V). It means 120 V * 9mrad/V = 1,08 rad pp at 9 kHz, this is a frequency variation of 9,7 kHz

the PMC error signal sees ~1 V pp (according to a 1.5 Vpp Error signal and a PMC pole of 781 kHz. This would mean

that either the frequency of the laser is sweeping by 520 kHz (this is not visible on the ML_PZT nor on the ML_FREQ_I_MONIT) or that the PMC is shaked around the laser frequency.

If the latter the doppler effect on the transmitted beam is a phase mdulation of pi/781kHz*520 kHz = 2 rad_pp at 9 kHz, this is 18 kHz.

The 18 kHz are managed by the IMC loop and would give rise to 9 kHz on the EOM and 9 kHz on the ML_pzt ( 1 mVpp * 10 * 1.2 MHz/V = 12 kHz).

Therefore it seems the PMC is shaked around the ML frequency due to some instability in t e PMC loop.

9 kHz is close to the mechanical resonnance of th ePMC piezo. It would worth to measure the PMC OLTF and check that the electronical compensation of the resonnance is still well tuned.

 

Images attached to this report
Search Help
×

Warning

×