ITF State: SINGLE_BOUNCE_WI
ITF Mode: Commissioning
Quick Summary: IMC and RFC locked; all Suspensions loops closed, all SBE loops closed.
Activities ongoing since this morning: Infrared Cavity relock in progress.

No DMS alarms received since the last shift.

At 20.00 UTC the WI-CH was switched off in order to cool down the CP.

At 21.00 UTC HWS-INJ acquisition started and at 21.09 UTC WI-RH  was switched on.

Starting from the entry 56320, at 06.59 UTC I stopped the HWS-DET acquisition (WF 500) and the NI RH steady state curvature can be seen in figure 1 and its centre coordinates are Y=(-0.06 +- 0.03) cm and X=(2.84 +- 0.05) cm.

At 07.21 UTC I started a new HWS-DET acquisition and at 07.26 UTC NI CH was switched on @ 368 mW. The NI CH steady state curvature can be seen in figure 2 and its centre coordinates are Y=(0.16 +- 0.06) cm and X=(-0.7 +- 0.1) cm.

There was a misalignment of (3.54 +- 0.15) cm in the horizontal direction and only (0.22 +- 0.09) cm in the vertical direction. So, I decided to move the CH in the horizontal direction, but several issues were found with TCSPicoNI which did not allow me to improve the alignment (see entries 56326 and 56328).

At this point, I set the NI CH power of June 28th (see entry 56314):

At 16.37 UTC HWS-DET acquisition started in order to see the RH cooling phase and at  16.52 UTC I switched off the NI RH.

At 19.55 UTC HWS-DET acquisition stopped, nothing of interest emerged from this measurement.

Further investigations are needed to understand what happened to the picomotors on the Hot Mirror. These will require accessing the bench.

As far as the problems reported to move the NI_HM_tx/ty picomotors we tryied:

• stop/restart the TCSPicoNI server: no effects
• reset (OFF/ON) the controller: no effects
• swap WI and NI controllers: no effects

From the software/config point of view:

• the ActuatorApp corresponding software (version v5r1p1) is unchanged from 2018
• TCSPicoNI server config file is unchanged from 2016

We tryied to send command from a terminal via cm send just to exclude any problem from the Python client side but we had the same result.

The behaviour is that while moving both tx and ty channels in Forward direction, logs from the server report the move is performed but from the HWS we see no move at all,  while moving in Backward direction the move is reported as not performed by the controller. Correspondig logs below.

2022-07-01-12h23m11-UTC>INFO...-MoveRel NI_HM_ty F 5500.000000 command received from position -53337.000000
2022-07-01-12h23m15-UTC>INFO...-Memory Used increase, cur. 3884.00(KB), inc. 24.00(KB)
2022-07-01-12h23m19-UTC>INFO...-Ping command received
2022-07-01-12h23m40-UTC>INFO...-Ping command received
2022-07-01-12h23m51-UTC>INFO...-Ping command received
2022-07-01-12h24m09-UTC>INFO...-main> Stopped at position = -47837.000000
--------------------------------

2022-07-01-10h30m06-UTC>INFO...-MoveRel NI_HM_tx B 5500.000000 command received from position -50365.000000
2022-07-01-10h30m08-UTC>INFO...-main> Stopped at position = -50365.000000
 

Check to hear the picomotor  noise from outside the TCS bench enclousure were inconclusive. Inspection on the bench itself  seems needed., 

The shift was dedicated to the planned TCS activity NI CH centering measurements performed by C. Taranto. We found an issue with TCSPicoNI,  we tried to stop and restart the process and to manually switch off and on the driver but we still have problems. 13:50 UTC I went into the TCS room in order to swap the NI and WI picomotors driver in order to see if it was the problem an investigation is ongoing, afternoon operator was informed about all situation.
Activity still in progress.

No DMS Events to report

Other
Vpm
10:47 UTC TCSPicoNI not working properly, so I stopped and restarted the process.
TCS
around 12:05 UTC F. Carbognani went into the TCS room to manually reset the PC unit that controls the Picomotors of the TCS benches in order to fix a problem.

I have been asked to check the seismic noise during the time I did the FFT.

So I reploted the FFT of the FC control signal with BPC ON in blue (Jun 17th 12:20 UTC) and OFF in purple (Jun 4th 02:00 UTC, time stamp is incorrect in the plot).

The excess of noise below 0.3 Hz in the signals AFC_GR_FCEM_AA_TX/TY and LFC_GR_PD_RF_5MHz_I_CAL while the BPC is ON cannot be explain by a higher seismic noise.

On the contrary the broad peak between 0.3 Hz and 1 Hz in LFC_GR_PD_RF_5MHz_I_CAL purple trace (BPC off) could be explained by higher seismic noise at those frequencies.

ITF State: SINGLE_BOUNCE_NI
ITF Mode: Commissioning
Quick Summary: IMC and RFC locked; all Suspensions loops closed, all SBE loops closed.
Activities ongoing since this morning: no activities ongoing

No DMS Events to report

This morning we wanted to analyze the last configuration of the DAS settings. A first comparison of the arm mismatch between 28th (fig.1) and today TCS settings (fig.2) shows that in the last configuration the West arm increased the mismatch from ~1.2 to 1.65 while the North stays almost unchanged.

Once the CITF locked, we noticed that the shape of the sidebands on the phase camera was very bad (fig. 3). Thus, we tried to improve the shape of the sidebands by acting on some alignment DoF.
In fig. 4 a summary of the first lock of the CITF were we explored the behavior of the sidebands with respect to both the PR alignment and input beam position. As we can see, while adding an offset on PR_T{x,y} didn't produce any noticeable change in the SBs, adding a negative setpoint to the Y DoF of the BPC loop did increase the mag of both sidebands.
Nevertheless, if we look at the PC images for the different BPC Y steps (fig. 5-11) it's hard to see a clear improvement.

To be noted, because of the optical configuration of SIB1 bench (in particular M7-M8 periscope), adding a vertical shift to beam entering on the bench will results in an horizontal shift at the output of SIB1.

Moreover, we noticed an unexpected behaviour while applying the shift on the BPC loop. We changed the offset with the arms locked in order to have all the AA loop on, including PR_{X,Y} and BS.

Considering the vertical shift of 500µm of the BPC and the magnification of the INJ telescope, we could expect an horizontal shift on the PR of few mm that should be corrected by the AA loop. Instead, except for a drift of few µm in Y, PR almost didn't move (fig. 12) while looking at the ASC_{N,W}I_T{X,Y}_LF_B{7,8}_Q_10Hz demodulated signals it appears that we induced a beam shift on the input TMs of few mm.

Because of the IBz loop on the IMC, we could not easily study a vertical shift of the beam with only the X BPC setpoint.

At the end, we reverted all the changes on BPC settings.

After the ISC shift (Entry 56318), at 20.52 UTC the NI-CH was switched off in order to cool down the CP.

At 22.19 UTC HWS-DET acquisition started and at 22.27 UTC NI-RH  was switched ON.

The bad behaviour of SR angular control can be better understood adding a plot of the longitudinal correction. Saturation of actuators and bad balance of actuators can cause angular oscillations when they occur together. This is a typical one year old situation, occuring when the lock acquisition strategy was far from being well tuned. An activity on SR actuators balancing could mitigate the problem of angular stability, but very likely will not fix the problem of lock acquisition.

The planned ISC activity on New TCS working point exploration (Casanueva, Pinto), started at 14:00 UTC and went on without major problems for the whole shift.
At 21:00 UTC Taranto (TCS) started from remote the NI RH switch on for CH centering measurement.
TCS activity still in progress.

No particular operations to report.

Parallel activity:
SGD: Automation (Bawaj, Holland)

The first part of the shift was dedicated to continuing with the morning activity of exploring the input beam alignment. The target was to improve the shape of the sidebands, that showed a vertical alignment mode. An offset was added to the BPC shift DOFs and we checked the behaviour of the dithering error signals and the input mirror centering error signals. A dedicated entry will be posted.

Then we tried to recover the lock of the CITF and progress with the lock acquisition. HOwever, we were not able to lock the CITF in a stable way. The few locks we had were achieved by misaligning the SR significantly (10urad). We were not able to realign the SR and keep a stable lock. Moreover, at some moments the SR local controls were showing a big movement of the SR, of several urads, without any loop being closed on it. The maximum sidebands we reached were 0.06 for the 12MHz and barely 1mW for B4 DC. Figure 1 shows a trend of the CITF lock attempts, with the SR local controls as well.

We contacted Claudia at the end of the shift and we leave the ITF in single bounce for the TCS activity.

We continued the work on the FCEB bench. 

1. Installed another lens in the IR path to collimate the beam

In the previous configuration, the IR PD is installed on the focal plane of the 500mm lens, this beam has a quite large divergence, so we suspected the low power on the IR transmission was due to the large beam size on the PD. So we installed a 100mm lens and extended the IR path much longer, the new version of the scheme and the picture is shown in pic 1 and pic 2. 

We could reach a maximum of 11V IR transmission after this adjustment. Still few volts are missing compared to two weeks ago, which we think could be due to the bad alignment of the IR filter. Further adjustments will be done.

2. Changed the green beam splitter from 90:10 to 10:90 (R:T)

Today the new beam splitter arrived, so we changed it and realign the green PD and the PSD. Now we have about 7.7V of green transmission. The filter in front of the PSD has been changed to ND = 1 from ND =2. 

The triggers for the locking, angular control loops, and the offload has been restored to the old value(5V). 

At the beginning of the shift, the ITF was in SINGLE_BOUNCE_WI: after a brief realignment the infrared cavities were relocked at 6:21 UTC.
The shift was dedicated to the planned ISC activity, locking and ITF characterization, carried out by Mantovani and Boldrini. The work proceeded during all the shift without major issues.
From 7:20 UTC to 7:40 UTC, under the request of the commissioning Crew, I performed the following Scan:

7:20 UTC - CARM_SET_scan(2)
7:30 UTC - SCAN_TEM0(5)
7:34 UTC - SCAN_TEM2(10)

Activity concluded at 14:10 UTC, infrared cavities left locked.

Other Activities carried out during the shift:
SGD: SGD: RTL optimization (Guo, Ding).

DAQ
The SQZ team reported that, since the 26 of June, the ENV signals related to the Filter cavity End Building (FCEB) were no more available. Upon investigation, I found that the related Slow Monitorning Box (ENV-FC-END) was not reachable anymore.
Thanks to the intervention of Cortese the connection was re-established at around 9:35 UTC and, after a restart of the process EnvServerSqz, the signals were available again.

Summary of settings:

Yesterday, at 21.28 UTC, NI and WI DAS powers were changed from the “28th June” settings to “29th June” settings. 

HWS-INJ acquisition was started at 21.18 UTC (before powers change) to control the transition. The acquisition lasted for 4 hours and showed the curvature change in Fig.1.

Actually, the OMC FSR should 834MHz not 864MHz. This makes the spacing of the modes in MHz in the figures is 3.5% wider than it should, due to the wrong conversion of time into MHz.

The spectrograms of the microphone (ENV_EDB_MIC) and accelerometer (ENV_EDB_ACC) make in evidence the acoustic and seismic noise variations in DET-Lab after the last actions to set-up the supply inverter frequency of that air handling unit (AHU), Figure 1 and Figure 2. In both spectrograms, a significant noise reduction is visible after each inverter frequency reduction action. The rms signal of the microphone shows a noise reduction of about 40% in the band (1-16)Hz and of about 70% in the band (16-512)Hz having set up (step by step) the supply inverter frequency from 45 Hz to 35 Hz, Figure 3.
Moreover, the evidence of noise reduction is visible also in the other attached Figures concerning the acoustic and vibration sensors, also in the squeezing area (ENV_EQB1*). General important noise mitigation was achieved in the bandwidth ~(10-100) Hz, Figure 4, 5, 6,7, 8.

More analysis will follow.

I have looked at the downgoing scan (so it is further away from the steps of the fast scan which will make the relation between the temperature of the OMC, and the temperature of the copper plate measured by the thermistance more linear). Starting from 09:32 UTC.

Also roughly calibrated time into MHz by using the OMC FSR spacing of 864MHz. And then indentified a few modes using the camera image (but I did not check all of them). The power shown in the following figures is B1 PD3 multiplied by 1000, which should be the power transmitted by the OMC, as B1 PD3 looks at a 0.1% pick-off.

Figure 1 shows the FSR scan around the order 0, 1 and 2 modes. WIth the carrier TEM00 highlighted in red. The tick markes show the 6MHz and 56MHz, LSB and USB.

Figure 2 shows the same with tick marks for the 56MHz LSB order 0, 1 and 2 modes.

Figure 3 shows the same with tick marks for the 6MHz USB order 0, 1 and 2 modes.

Figure 4 shows the same with tick marks for the 6MHz LSB order 0, 1 and 2 modes.

Figure 5 shows the same with tick marks for the 56MHz USB order 0, 1 and 2 modes.

Figure 6 confirms that on the phase camera the LSB (both for 6MHz and 56MHz) has much higher power  ( by a factor few) than the USB.

The mode mismatch mode (order 2) is much higher in relative power for the USB (both 6MHz and 56MHz) at ~110% of the TEM00, than for the LSB (both 6MHz and 56MHz) that are at about 50% of the TEM00 opwer.

/users/mwas/OMC/OMC_scan_20220630

ITF State: SINGLE_BOUNCE_WI
ITF Mode: Commissioning
Quick Summary: IMC and RFC locked; all Suspensions loops closed, all SBE loops closed.
Activities ongoing since this morning: Infrared cavities relock in progress.

The goal of the activity is to use the arm cavities as diagnostic FP to measure HOMs of the sidebands which resonate into de CITF.

We locked the DRMI with a positive CARM SET (3000 Hz) and made a scan of the CARM SET toward positive values. See pic1.

We used the information on the position of the SB in the arm cavity spectrum (pic 2, 3) and the spacing of HOM to identify SB HOM during the arm scan with locked CITF. (pic 4)

The expected position of the SB HOM agrees well with the measurement. We could double check the identified HOM by looking at the shape of the transmitted beam on B7 Cam.  A video of the B7Cam during the scan can be seen here. (link)

In particular we focused on the HOM2 which can be used to estimate the mismatching of the SBs. As can be seen from the video, for the four SB HOM2 the brightest peak is a mismatching/astigmatic mode (pic 5). (Note that there is a splitting of the resonace frequency of HOM of the same order due to astigmatism of the cavity),

In order to assess the mismatch we cannot measure directly the height of SB fundamental modes, as CITF unlocks when they become resonant in the arms.

We can instead compare the power of the SB mode of order 2 (P_HOM2_CITF) measured on B7/B8 PD during the CITF CARM set scan and the height of the SB TEM00 measured on B7/B8 PD during the simple arm scan (P_TEM00_SC)

We have the following relations:

P_HOM2_CITF = 1/2 * P_in * G_PR * T_ARM * MM

P_TEM00_SC = 1/2 * P_in * T_PR * T_ARM

Where P_in is the input power on the BS, G_PR is the SB recycling gain, T_PR is the transmission of PR, T_arm is the arm cavity transmission and MM is the mismatching.

The mismatch can be then computed as  MM = (P_HOM2_CITF/P_TEM00_SC)*T_PR/G_PR

We will do as slower scan around HOM2 to have a more precise estimation of the peak height.

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Other notes

1) We noted that locking DRMI with the opposite offset wrt the usual one brings it to a lower level of 12MHz_mag (roughly 0.08 instead of 0.1). The power could be fully recovered by adding an offset on the PR angular TY angular loop.

2) In order to have a more precise estimation of the peak position during the scan we made available a new CARM SET channel sampled at 10kHz  (LSC_CARM_SET_FS).

This afternoon we continued the work of yesterday evening, that is to recover the lock acquisition and study this particular ITF configuration. Here the main changes we did and what we could observe:

• initially we left unchanged the DRMI lock, both on 1f and 3f; we could see that the PR alignment loop could already benefit from an offset on TY and we put it (-0.005); later, we added this possibility in the Automation, and the offset is set just before the finalization of the DRMI lock in 1f;
• the DRMI lock itself was really smooth for more than one half of the shift, while in the last 2 hours it became much more difficult;
• the CARM handoff to the infrared on the MC was working without any issue; initially, we performed the DARM handoff by hand following the same methodology as yesterday: increase the arm transmitted power to 40 mW, then perform the DARM handoff to B1p_56MHz_I, then change the control filter; DARM calibration was set to 2.2e5;
• then we verified the parameters and reached the same step with the automation, which also brought us to 50 mW arm powers, as usual; we immediately saw a drop of the DARM gain by basically 50%; we reverted the last step and moved back to 40 mW, but we saw no change; the DPHI monitor also showed a change; even after retuning the phase (at later steps) did not cure this, and eventually we put the DARM calibration to 5e5 for the rest of the shift (Figures 1 and 2 the trend, Figure 3 the DARM OLTF after the drop);
• given that the DARM handoff happens now at 40 mW arm powers, we decided to move all the other CARM offset steps: now, the ramp after the DARM handoff stops at 75 mW instead of 50; STEP1 is now 100 mW instead of 80 and STEP2 is 200 mW instead of 160;
• we managed to get to STEP3 many times, but we suffered many unlocks, mostly at STEP2 and STEP3; the main causes were bursts of noise at 150 Hz and oscillations at around ~12-13 Hz (Figure 4); we cured the former by tuning the gain of the CARM loop injecting noise on the RFC, while the latter are still unexplained (Figure 5, CARM OLTF before the gain increase); we also had one unlock thanks to a 9 Hz oscillation and one at a much lower frequency, around 1.2 Hz;
• during the shift we consistently had a PR_TY offset, and we generally increased the gain of such loop during the CARM offset reduction; to recap, we have now three places where we put offsets on PR before CARM_NULL_3F: just after closing the control at DRMI 1f, between the CARM handoff on IR and the DARM one; again, at STEP3.

We left the ITF in the Single Bounce (WI) configuration, which we added in ITF_LOCK (in the "all" menu).

Several flaws in the code were removed. The most important were:

- log flooding issues;

- cm_send flooding.

For the first problem, log writing was removed from the states run() and some were substituted with notify()

For the second problem, a boolean flag was introduced whenever a risk of sending multiple cm_send was present.

Automation tests were difficult due to frequent INJ relocks and after some time they were moved to the next automation shift.

The planned ISC activity on locking and ITF characterisation (De Rossi, Capocasa) started at 07:00 UTC and went on without major problems for the whole shift.
No particular operations to report.

Parallel activity:
SGD: RTL optimization (Guo, Zhao)