We did not manage to analyze the results of the free swinging mirrors with the kick measurement made yesterday (probably because they were not excited enough).

For this reason this afternoon we performed again this measurement, but we first opened the dampers, we manually put in down the ITF and then we applied the corrections (more than once, to keep the mirror excited).

The first kick was done at 15:51:36 UTC, and the data were analyzed 3 minutes later taking the peaks during 220s (so it cannot be defined "hot" itf measurement).

We obtained 2% mismatch for the north and 1,6% for the west (see plots)

During the first hour of the lock that started around May 7 16h50 UTC, the ITF was kept in LN2 and the SR misalignment was not yet set for an optimal BNS range (plot1).
During this LN2 part, the Hrec bias was better over the full frequency band 20-1000 Hz (plot2), without the usual wave we observe once SR is misaligned optimally and ITF is in LN3 (plot3).
Plot4 shows also versus time the modulus and phase of the hrec/hinj values also in plots 2 and 3.
Plot5 and plot6 show the hrec/hinj modulus and hrec/hinj phase for some of the lines. They show also the value of SRCL_SET_TOT and the evolution of DCP and Optical gain during this time period.
They show that before the rapid setting of SRCL_SET_TOT around 50 and the transition from LN2 to LN3 (that occured around 18h25 UTC), the phase and modulus of hrec/hinj are closer to 0 and 1 respectively (as already shown by comparing plot 2 and plot3), while the DCP estimated by Hrec is around 400 Hz and the Optical gain estimated by Hrec is around 2.2e+9.
A specific behaviour: before the transition, the phase of hrec/hinj of the line at 77.5 Hz is to high (around 0.06 rad) and the modulus of hrec/hinj of the lines at 77.5 Hz is too high (around 1.03).
Also, we can remark that during the transition, hrec/hinj modulus can vary a lot (up to 10%) for some of the lines before going to a stable value (see plot7, which is a zoom of plot5).
Those better hrec/hinj values when SR is not yet LN3-misaligned may be a hint for Hrec using an optical response model not adapted to SR misaligned configuration.
The large variations of hrec/hinj during the transition may be also worth to investigate.

ITF stable locked at LOW_NOISE_3_SQZ (Science Mode) for the whole shift. 

We can apply the same logic to the B1p and B1s photodiodes to confirm whether they give similar results to those obtained with the phase camera.

In order to better compare, we can use the phase camera and also compute the sidebands dark port transfer function and calibrate their power at the dark port. The sum carrier + sidebands should give a similar value to the one given by the B1p and B1s photodiodes.

Figure 1. shows the calibrated phase camera powers (carrier and sidebands) after 1 hour of science mode (30th April).

Figure 2. shows a comparison of the phase camera calibrated power vs the calibrated B1p and B1s photodiode signals. For comparison the carrier only power and carrier + sbs signals are shown. The carrier + sbs power seems in agreement with the B1p PD2 and B1s PD1 photodiodes (B1p PD1 had weird results, maybe because of the shutter being on at some point).

Analysis of the OMC scans might show if the relative power between carrier and sidebands matches that seen by the phase camera.

Upon reaching the site, I've found the ITF in LOW_NOISE_3_SQZ and Science Mode.
At 14:00 UTC I set the ITF in Commissioning Mode to allow the planned activity for the afternoon (Characterization for EM RH tuning) carried out by Nardecchia, de Rossi, Melo, Gouaty (see report #64205).
At 14:17 UTC the ITF was unlocked by De Rossi and Melo by performing a kick on the end mirrors, followed by a brief period at LOCKED_ARMS_BEATING (from 14:28 UTC to 14:51 UTC).
At 16:06 UTC we reached CARM_NULL_1F, and we waited one hour before performing the OMC Scan (scan done from 16:08 UTC to 16:31 UTC, see report #64206).
After that we reached LOW_NOISE_2 at 16:50 UTC, we waited 90 minutes to take reference data.
ITF back in LOW_NOISE_3_SQZ and Science Mode from 18:31 UTC.

Guard Tour (UTC):
17:06 - 17:36
19:01 - 19:28

The goal of the shift was to characterize the ITF working point with the following RH powers:

The actions performed during the shift are listed below:

13.08 UTC: ITF relocked in LN3

14.18 UTC: ITF manually unlocked to perform input beam mode matching measurement with the free swinging technique and green laser scan (performed by Suzanne, Camilla and Matthieu).

                    See detailes in 64204

15.03 UTC: ITF relocked in CARM NULL 1F

16.08 UTC: OMC scan started (performed by Romain and Andrea)

16.30 UTC: OMC scan ended 

16.52 UTC: ITF relocked in LN2

After 1.5 hr in LN2, at 18.20 UTC, Andrea will proceed with the lock acquisition.

The main ITF signals during this afternoon are shown in figure 1.

Figure 1 shows the scan of the OMC performed from 16h08 utc to 16h30 utc, after waiting for 1 hour in CARM_NULL_1F.

Figure 2 shows a zoom of this scan around a Free Spectral Range.

Assuming a calibration factor of about 4800 for B1_PD3, we have: ~75 mW on the first order mode, ~29 mW on the second order mode, ~200 mW on each of the third and fourth order modes, ~70 mW on each of the 5th and 6th order modes, ...

This afternoon we performed some measurements to verify the mismatch towards the arms. The last measurement done is reported in #63374.

First, we performed the free swinging method, giving a kick on the end mirrors (with the dampers opened). The GPS of the kick (we gave the kick simultaneously for the West and North arms) is 14:17:00 UTC.

However, when analysing the data we could not find reasonable values of mismatch. We need to verify if there is any problem with the Matlab code to debug, or there was something wrong with the measurements. In Fig. 1 we can see the time window of the free swinging mirrors. To be noted that the west arm starts swinging after roughly 15 seconds with respect to the North Arm. On Fig.2 we can see the surposed flashs of B7 and B8.

Then, we perform the measurements with the Green Scan. The GPS in this case 14:30:43 UTC (Fig 3). Figs 4 and 5 show the scans of the TEM 00 mode and TEM 02 mode respectively. In this case, for the north arm we found 3.3% and 1.4% for the west arm, as shown in Fig. 6.

In order to try to mitigate this problem, we have increased the shutter pulse duration from 20 ms to 40 ms for both B1_PD1 and B1_PD2. The SDB2_dbox_bench process has been reloaded at 14h52m27-UTC.

Upon arrival, I found the ITF locked and in SCIENCE mode.

At 6:05 UTC I set the MAINTENANCE mode. Here is the list of the activities communicated to the Control Room:

- Cleaning of the Central Building and the DET Lab (external firm managed by Menzione);

- TCS chiller refill (Menzione);

- Replacement of the electric post-heating coil for the AHU 1_SX of the Mode Cleaner (external firm managed by Soldani);

- Checks on the HVAC plants (Soldani);

- ELE_QGBT process update (Ballardin);

- ENV_MCB_MAG_N magnetometer substitution, see #64189 (Paoletti)

During the shift, I performed these periodic tasks:

- At 6:10 UTC I set the SINGLE_BOUNCE_NI state. OMC locked from 6:30 UTC to 6:35 UTC. OMC scan performed from 6:45 UTC to 7:06 UTC;

- Check of IMC working point and position from 7:20 UTC to 7:30 UTC;

- Acquisition of TCS thermal camera references at 7:47 UTC;

- At 9:00 UTC checks on TCS powers (see table below for results);

At 9:03 UTC the SNEB horizontal position control loop opened. I closed it at 9:28 UTC.

NCAL flag on DMS became red at 8:20 UTC. Experts informed.

As requested by Degallaix, I performed a slow FSR scan with the green laser from 10:44 UTC to 11:13 UTC. After that I set the PREPARE_SCIENCE mode.

During the lock acquisition a CITF alignment was required. The SUS_PR and DRMI_LOCK Metatron nodes got stalled, requiring a restart of the latter.

I left the ITF in LOW_NOISE_3_SQZ state and SCIENCE mode at 13:10 UTC.

This morning between 8:00 and 10:25 UTC I slightly changed the position of the central crop in B1p camera image, in order to better catch the central spot. See previous crop in first attachment (in LN3), current one in second attachment (in arms locked)

VPM process has been reloaded and, after a fix, the 2 new flags are correctly display. I'll watch the new flags regularly in the following days to check that the parameters are correct.

Following the CO2 power scan done by the operator (see entry 64186), I just slightly tuned the CH powers to restore default. The action concluded at 10.03 UTC.

Today also FIAMM01 (Carabinieri) had some flyover near CEB (08:40 UTC)

The estimated distance is ~ 200m, the height was ~ 200m (credits: flightradar24), well inside the NOTAM area.

The signal is very clearly visible in the CEB microphones. The ITF was unlocked (maintenance).

The weather station did not transmit during a long time (to be quantified). I disconnected it and checked the serial-to-Ethernet on bench with an universal power supply, since it is very difficult extracting its own jack from the box on the wall. No response, and FPGA very hot. No spares of the same kind presently available, only one Netcom Plus 211 with a different supply connection.

I leave the Meteo station disconnected and the box opened, as long as we find a solution.

The process ELE_QGBT interrogates different electrical nodes; when a node does not respond the process automatically goes into the Error state. Obviously, data related to that node is not sent to the DAQ. When the problem disappears, the process automatically goes in the Golden state (so it not necessary to restart the process from VPM) and the slow monitor date is sent again to DAQ.

Today at 10h24 LT I put in operation a new version (v6r9) of this server to try to detect nodes generating problems. In this new version when a node does not respond, the ELE_QGBT goes in Active State and not in Error State.

Figure 1, the 157Hz bump decrease in the first hour of each lock, Figure 2 during the shift yesterday it did not decrease because the MICH SET loop was intentionally disable for an hour, and then MICH SET adjusted quickly by hand. 

Figure 3 confirms that RIN coupling due to a MICH offset is the dominant coupling path fo the 157Hz bump. Blue was with a large RIN coupling to DARM, red  and yellow are with the coupling intentionally increased by adding a MICH offset in the wrong direction, and green purple and green are with the MICH offset adjusted to minimize the RIN coupling (at 1.5kHz).

Figure 4. As seen benfore when the PRCL offset is adjusted to minimize the frequency to amplitude conversion on B2 (blue and red lines), the B2 Audio spectrum is much cleaner, especially at high frequency.

Figure 5 and 6 what is surprising is that looking at the B2 quadrants. In the vertical direction the coupling of frequency noise (227Hz line) decrease in the vertical direction by a factor few, but in the horizontal direction there is no significant change. Does that mean that the coupling has a significant contribution of HOM? Note that this is true only for B2 QD1, on B2 QD2 the line at 227Hz is not visible in neither the H nor V direction, at any of the times. And on both quadrant the sum channel sees the line clearly and decreases by a factor 10 when adjusting the PRCL offset.

/users/mwas/ISC/RINanalysis_20240506/analyseRIN.m

The probe has been removed today from the MC tube, during the maintenance.

The ENV_MCB_MAG_N magnetometer was defective as of October 2, 2023 at 00:03:05 UTC.

Today we changed it with a new one (MFS-06e). We also had to use a different type of cable (the new magnetometer uses a different connector), via an adapter.

The signals seem to have returned to normal values.

This morning, the threshold on SDB1_slow_shutter_OMC1_T1_fast_RMS used to monitor the closing of the slow shutter has been adjusted to 6e-9. DetMoni restarted at 07h19m23 utc.

ITF in Science mode for all the shift.

Guard tours (time in UTC)

From 21:00 to 21:30; from 23:00 to 23:30; from 1:30 to 2:00; from 3:30 to 4:00