Today as a side effect of the NAC problem (49388) the 2W amplifier at NE went in safety mode. We turned it on and restored the green power at 15h35 UTC (1st plot).

At the WE we had the green switched off since Friday the 11th. We suspected that the AOM was not working because we didn't have power at its output. For this reason we measured the input and output signal of the AOM RF amplifier, finding that everything was working correctly.

The 2nd figure (VCO_out) shows in yellow the output of the electric box "VCO_out" (which is a monitor of one of the signals going towards the mixer: this seems to be fine) and in pink the monitoring signal AOM in, which is coming out from the mixer (resulting from mixing VCO_out with a DC coming from the DAC), which is going to be amplified to 2W and drive the AOM.

The 3rd figure shows in yellow the actual signal going to the RF amplifier, whose amplitude is 300 mVpp: this corresponds to -7 dBm of RF power. The amplifier has a gain of +38 dB, so the power going to the AOM is +31 dB.

The 4th figure shows the output of the amplifier (we paid attention to switch off the power supply before remove the load). We measured it with an attenuation of 23 dB, so we expect to measure 8 dB (1.6 Vpp) on the oscilloscope. It is what we measured (in yellow).

Once everything was plugged again we had some light out of the aom, so the conclusion is that it was probably a bad connection.

We turned on the amplifier on and the last figure shows the trend up to now.

After the today problem with the network and the slave diodes we recovered the alignment obtained on Friday. To be noted that before the signal interruption, IMC stayed locked in drift control and was stable during the whole weekend without major issues (see fig. 1).

We then closed IBz loop and finally close the AA in full bandwidth. The system appears to be stable, we will check the behavior overnight.

This morning at around 4:30 UTC the issue related to the ipcam37 has triggered again ( see entry #49456 ). Thanks to the help of S. Cortese and A. Masserot the network was restored, the various rtpcs were restarted and the SBE loops available were closed. 
Other issues/activities carried out afterward:

• The LNFS resulted in the wrong state and returning incorrect values. With the remote instructions of F. Carbognagni and with the help of J. Casanueva it was returned to its standard state at 11:10 UTC.
• Since the Ipcam issue it was not possible to interact with the Suspension DSP Boards of SIB1, WI, WE PR and SR. Thanks to V. Boschi all the signals were restored.
• Most of the Environmental modules were unavailable. Thanks to Carbognani, Cortese and Gherardini almost all devices are now reachable again. imms11 and imms13 are still to be reconfigured.
• TCS WI CO2 laser cooling cabled ( see entry # 49453 ).

Thanks to a partial restore of the signals and suspensions the INJ team was able to start the recovery ( see entry #49452 and #49457 ). INJ Activity completed at 15:50 UTC and IMC left in full bandwidth.
TCS activity in Central Building still in progress.

SBE
At 15:00 UTC SDB2 loops started to ring. I contacted the H.J. Bulten to inform him of the issue, investigation in progress.

Actions performed:
- Use bidi-transceivers between the Computing room (blue color) and the DAQ room (red color). This avoid to add new physical optical fibers. Bidi-transceivers uses one single fiber for the Rx and Tx transmissions (one wavelength for each direction)
- Remove DaqBoxes chains:

• DET Elec room: DaqBox 27, 52, 51
• INJ Elec room: DaqBox 26
• EEroom: DaqBox 54, 37, 42
• TCS Elec room: DaqBox 31
• CEB plateform BS rack: DaqBox 33
• DAQ room: DaqBox 25, 47

- preparation of new RTPC connections in computing room (timing and optical links)

- Installation of MuxDemux V2 13 in computing room.

- Installation of MuxDemux V2 17, 15, 19, 20 in DAQ room

- Re-cabling of the MuxDemux V2 Tolm network (DAQ room and Computing room) except in end buildings (MC, NE, WE).

- change the daq path for suspensions Tolm optical network. Upgrade of file setup.dat (according to the network changes)

- Fix an issue on the suspension to_from.dat file

- Remove the timing chain for DaqBox 24 and 45 (SQZ) and for DaqBox 20 and 47 (SIB2)

During the operations to recover the INJ system, we had a sudden drop of power of the slave laser. This was due to a drop in the currents of both pumping diodes (see first plot). We managed to restore the usual current values by acting on the knobs in the EEroom. This was enough to recover the lock at the normal value for the slave laser and, as a consequence, for the downstream devices.

By a quick look, we did not find a possible origin in environmental probes (second plot), besides a small glitch on the ENV_CB_ELECTRIC. Since it happened to both the diodes and rather quickly, it does not seem related to the ongoing ageing of the diode2.

To be investigated.

Works in progress for INJ.

The  same troubles occurred once more this morning around 05hUTC due to the camera  "SNEB_FrontRight" - ipcam37 even if the   UPnP service  was disable on all IP cameras last week.

There is  a camera spare available  in the CEB-LAPP-office to replace  with the faulty  one . It will helpful if the swap could be done soon .

As consequence all  the ITF Ethernet devices have to be reconnected to the network.

The scheme of the previous Tolm network

This morning the pipes for the cooling system for the new WI CH CO2 laser have been cabled.

Due to the lack of essential signals, the Laser beam has been blocked on the laser bench for safety isues.

ISYS status: BPC with only static corrections, PMC scanning mode, mirror flipped up to block the beam on the bench, ML, SL, Amplifier on.

We wait for the recovery of the signals to resume the system.

State of Virgo: Unlocked.
ITF Mode: Upgrading.
Quick Summary: Most signals and cameras are not acquired due to an issue with ipcam37. RTPC and Hameg signals are missing.
Activities ongoing since this morning:
- Recovery of the missing rtpc signals ( A. Masserot );
- ISYS system in safe mode ( A. Chiummo ).

INJ recovery continued on Friday, after Thursday problems with DSP card. The final status is (details later here): INJ locked from Friday evening, RFC locked, PSTAB working, Fmoderr tuned and AA in drift control. The system appears to be stable overnight with the exception of three short fast unlock (see fig.1). On Monday, we will test the automatic alignment in full bandwidth.
 

More details:
After the problem with MC suspensions we started back the alignment by closing BPC loop. We then looked for a MC_F0_Z position close to RFC TEM00 and tuned fmoderr to 0. Checking the RFC phase, we remarked a strong phase shift of the error signal of the RFC (fig.4) then we correctly tuned it (fig. 5).
Then, recovering the position of IB bench and MC to last alignment in which AA was working (49402) brought the system in an unstable state  (i.e. Tx/Ty of both MC and IB showed wide oscillation). Those oscillations were probably preventing AA system to work properly. We decided thus to move toward another previous position of IMC alignment by tuning directly the beam position on the MC_Cam (see fig. 2 and 3). Once the position finely tuned maximizing IMC_TRA and optimizing reflection, oscillations in Tx/Ty (in particular Tx for MC) were strongly reduced. Finally, we manually brought to 0 in  ACL the offsets in tx/ty/tz error signal for both IB and MC.
After that, we measured again the sensing matrix with AA and RFC loops open, by injecting noise (a line at 2 Hz) on each AA DoF (see table below):
 

In addition, to test the correctness of the new matrix, we individually tested again each degree of freedom by injecting noise, and verified that only the relative reconstructed error signal was acting.

We left AA loop in drift control.

TODO:

- check offsets on galvos
- check phase modulation of QD FF/NF
- close IBz loop
- close AA loop on full bandwidth

There was an error in the TOLM path  to reach  the DAC1955-SN02( WEB_DAC_ALS0 ) located in the DBOX_SN50( WEB_DBOX_ALS) from the rtpc9 .It should be OK now

The main activity of the shift was the INJ recovery; activity still in progress at the end of the shift.

Other activities communicated in control room:

• Restart of the green sources
• SBE-SQB1 Installation and functional testing
• TCS

We restarted the green source at NE. We did not encounter any problem.
However it seems that the DAC at WE is not working properly which prevent us to make the AOM work. 
We made a test with an oscilloscope, whatever the value that we were sending from ACL the output was 0. To be investigated.

From 14 to 18 September we installed the SQB1 multiSAS inside its minitower in the detection lab. Before hoisting we shortened the steel lifting cable length by two meters, in order to reduce the number of cable layers on the pulley to maximum 3-4 making the hoisting much more easy.

The electronics boards for the stepper motor drivers, voice coil actuators, geophone and Trillium have been installed and configured. Both sides of each of the signal cables are marked equal corresponding to the names on the breakout box at the North side of the minitower. The Geophone pre amplifier was removed and the sensor temporarily directly connected to the ADC.

Horizontal sensor positioning:
Both the geophone and the F0H0 LVDT are located near the electronics breakout box(north side) and oriented along the Z axis. On the opposite side of the top stage the Trillium is placed, its local north coordinate is pointing towards the +X direction (towards SDB1).

Linearized sensitivities of raw LVDT’s (um/V):

• F0V 240
• F1V 261
• F0H0 344
• F0H1 321
• F0H2 294

Tuning of the MSAS modes:

• IP-Modes horizontal: 45 mHz (X,Z)
• IP-Mode yaw: 370 mHz (Ty) *
• Intermediate filter (IF) tilt: 620 mHz (Tx,Tz)
• IF differential pendulum: 1.67 Hz (X,Z)
• GAS filter F0; 150 mHz (Y)**
• GAS filter F1; 120 mHz (Y)**

(* The remaining (torsion) modes are all below 20 mHz)
(** resulting in common and differential mode of 100 and 700 mHz respectively)

The payload mass equals 324 kg. The IP and intermediate balance mass writes 18.5 and 16.2 kg respectively. The SBE-SQB1 Minitower is closed and the electrical cables have been disconnected for the installation of the cable ducts and the final routing from the crates towards the Minitower. After reconnection we can start to close the control loops and define the initial control settings.

To be done:

• Replace vertical correction springs on the intermediate filter
• Replace geophone/seismometer board

Yesterday the probes placed last week on the WE ALS bench were connected. Now the following signals are available:

ENV_WE_ALS_ACC_Z:  PZT Vertical Accelerometer

ENV_WE_ALS_MIC: Microphone

ENV_WE_ALS_TEMP: Temperature inside the enclosure

ENV_WE_ALS_PRES: Pressure inside the enclosure

ENV_WE_ALS_HU: Humidity inside the enclosure

Nevertheless, after the installation, I realized that the  microphone signal had a very low amplitude. After checking the probe and the connections it resulted that the channel 1 of the Nexus amplifier, used for the ALS microphone, has a problem. It seem that one of the amplification stages does not work correctly, indeed by comparing the spectrum taken by using another Nexus amplifier they appear very similar, except for a gain factor (good Nexus channel: blue curve, bad Nexus channel: magenta curve).

At the end I connected again the microphone to old Nexus amplifier: so please consider that the microphone signal is not very significant. The bad board will be substituted in a couple of weeks.

State of Virgo: Recovery.
ITF Mode: Upgrading.

Quick Summary:

• IMC not locked;
• SBE loops closed with the exception of SDB2;
• SWEB, SR, SDB1 Suspension Loops Open; 
• SR-BS Valve close;
• TCS NI CO2 Laser OFF;
• Automation OFF;

Activities ongoing since this morning: 

• INJ recovery after DAQ work;
• SQB1 MultiSAS installation in DET LAB ( NIKHEF Team );
• DAQ Timing upgrade and system Recovery ( DAQ Team );

After DAQ team managed to give us back the signals for the Injection system, we started to recover the normal state. We enabled the control of the EIB, locked the PMC, managed to close the BPC loop and reduced the related corrections by acting on the usual M6-M8 picomotors, then aligned and locked the IMC cavity.

At some point, while trying to progress with automatic alignment (more on this soon), I (AC) deemed wise to discharge the integrator of the MC DSP card, as done several times in the past. Unfortunately, this time it resulted in triggering the guardian, but also - for reasons to me unknown - the impossibility to communicate anymore with MC suspension. The work is therefore suspended until tomorrow morning.

To the benefit of the DAQ team check, it is also to be noticed that we managed also to lock for some minutes the reference cavity.

We leave the PMC in scanning mode, BPC with static corrections, and the beam blocked on the Laser bench.

List of Activities carried out during the Shift:
- SQB1 MultiSAS installation in DET Lab ( NIKHEF Team );
- DAQ Timing upgrade and system Recovery ( DAQ Team );
- Activity on TCS CO2 Lasers ( I. Nardecchia, A. Rocchi );
- Recovery on the INJ System ( INJ Team );
- Recovery of WE loops Suspension ( V. Boschi ).

INJ, SBE, DAQ and TCS Activities still in progress.

After the issue of last Friday (49409) we decided to monitor the pickoff of the IR seed as it is after the 3 km fiber from CEB + fibered polarizer (in other words, the seed before being amplified in the SOA).

The average power is 2.2 mW and we registered fluctuations of about 48%. The oscillation period seems to be 14 mHz.

We compared to the measurement done at NEB in August  (49235), where the fluctuations are around 33% with a  period of 10 mHz.

The only difference is that for the NE measurement the IR seed was coming from the pickoff on the Laser Bench, while today for the WE the seed is the NKT laser in CEB. However this shouldn't make any difference since after 3 km the light should be depolarized.

We will take data as it is until tomorrow,to check if there is any difference day/night.