I received notification of WE PCal error via the DMS. The power on the Rx sphere is very unstable and goes close to 0. This must be related to the alignment of the WE mirror, which results in the PCal reflected beam going outside the sphere input port.
I have switched off the Pcal beam so the beam does not move around on the Rx bench. We will switch it on later (probably only on Monday, not being available in the next two days).
Today I re-enabled the etalon loops, using setpoints just slightly above the current temperatures, just to monitor the corrections:
These setpoints were changed online, and also in the configuration file.
The following information summarizes the directory structure and file naming convention for the measurements performed on the NI and WI instrumented baffles.
*** NI instrumented baffle ***
where
# is the measurement (SIG) number reported in the action list;ch1 = mono-axial reference accelerometer;ch2 = triaxial accelerometer, x-axis;ch3 = triaxial accelerometer, y-axis;ch4 = triaxial accelerometer, z-axis.*** WI instrumented baffle ***
The same file naming convention described above applies to the WI measurements.
An example MATLAB script (ReadInstrumentedBaffleData) is attached to show how to read the time-series data.
Plots showing the result of WI MIR actuation cheks are attached. If a voltage is generated by UL DAC (seen by the monitor inside the board), no effect is visible on the mirror orientation (fig 1). If the same is done with one of the other DACs, the rotation is well visible (fig 2).
Pcal NE switched on on July 31 at 7:55 utc.
On July 30 afternoon, we went to the laser lab to realign the ALS laser beam on EIB. We used the CEB_PD_GREEN_MONI photodiode as reference for alignement. The mirrors before the green generator cristal (EIB_ALS_M4 and 5) were realigned to it maximize the power in that photodiode. Then the mirrors EIB_ALS_M6 and 7 were realigned with the IR fiber, using the IR power send to WEB and NEB as reference.
For a reason we still don't understand, CEB_PD_GREEN_MONI photodiode cease to work from 15h to 16h. But it started to work again after we disconnected and reconnected the power supply and Vbias cable.
We recalibrated the CEB_PD_GREEN_MONI photodiode gain and offset in the DAQ so it estimates the total green laser power on EIB. And we changed the threshold values on the DMS for the photodiodes CEB_PD_GREEN_MONI and CEB_PD_IR_MONI.
The green beam was also realigned with the fiber photodiodes CEB_NARM_BEAT and CEB_WARM_BEAT, but this alignment can still be improved by playing with the pico-motors EIB_ALS_pico1 and 2.
The up-left coil looking from the rear side has an issue with the shielding of its cable https://logbook.virgo-gw.eu/virgo/?r=69386
Is that the same coil-magnet pair which is not responding to DAC actuation? Electrical checks should be done as a priority in any case, but if the up-left coil-magnet pair is the issue, then it makes it more likely that this is an electrical problem.
Yesterday and today we worked on the realignment and the relock of the two arms. We spent many hours in finding the alignment again, for both arms.
In the end we managed with a mix of procedures:
After a pause this afternoon to allow other activities, in the evening we managed to finally get some flashes.
We then started to work on the relock:
We leave the two arms locked, in standalone, using the single arms lock nodes.
The up-left coil looking from the rear side has an issue with the shielding of its cable https://logbook.virgo-gw.eu/virgo/?r=69386
Is that the same coil-magnet pair which is not responding to DAC actuation? Electrical checks should be done as a priority in any case, but if the up-left coil-magnet pair is the issue, then it makes it more likely that this is an electrical problem.
Plots showing the result of WI MIR actuation cheks are attached. If a voltage is generated by UL DAC (seen by the monitor inside the board), no effect is visible on the mirror orientation (fig 1). If the same is done with one of the other DACs, the rotation is well visible (fig 2).
ITF in UPGRADING - DOWN
Today's activities:
Arms recovery (Bersanetti, Boldrini, Majorana, Ruggi, Spinicelli, Was)
TCS auxiliary cooling system cabling - new data channels (Cavalieri)
ALS recovery (Lagabbe, Spinicelli)
The attached shows the excitation produced by opening and closing the doors of the SAS and piscina. The excited bump looks well matched to the 18.50 Hz one. Some small excitation of the 12Hz bump is noticeable as well.
We had a look to the effect of the sound wave pulses produced by repeated door opening and closing.
In the morning, while the HVAC was on, we performed a set of pulses with the door between the laser bench room and the minitower room. Figure 1 shows ASD of the microphones inside the laser bench room. They all see a bump at approximately 20Hz growing above the noise backround noise. We remind that the "LLR" microphone was positioned in the N-W corner of the room, at aproximately the beam height.
In the afternoon we repeated the same test, but the HVAC was off (also those of CEB) and we acted with the door between the Atrium and the laser bench. In Figure 2 (and Fig.3) the purple spectra correspond to the quiet condition. Two bumpy structures at approximately 12 Hz and 18.5 Hz are visible, in particular in the LLR microphone. In the excited condition (blue) microphones see again a peak at about 20Hz and also, less pronounced, growing bumps at roughly 40, 45, 55, 85,135 Hz (Figure 2).
Figure 4 (also 5 and 6) is a spectrogram of LLR mic over the time of this test. After the test is finished (about 13:13:30 UTC) additional pulses around 20Hz are seen (actually here the excited frequency is a bit lower, it looks more around 18.5Hz). These are due to Irene exiting the lab and opening/closing the doors of the atrium, the SAS and the piscina.
We would interpret these frequencies as acoustic modes of the room. We are also tempted to think that the 18.5 Hz bump seen in quiet condition is the same 20Hz mode excited by the door. We have excluded already it to be a resonant mode of the air ducts ( https://logbook.virgo-gw.eu/virgo/?r=69148). The frequency mismatch (20Hz instead of 18.5Hz) however needs an explanation.
In this logbook entry we will explain how the alignment of the North End Mirror has been done, using data from the Instrumented baffle.
The baffle interface shows the power and radial angle positions of the 120 sensors present. The baffle has 6 different sections, each of them with 4 columns and 5 rows of sensors.
The procedure followed was to:
Note that the power when you are above a sensor is of approximately 30 micro watts.
The current reference NTP time for some linux machines, including RTPCs, is taken from the local windows domain servers, backed by standard ntp references on the Internet.
It turns out that their pace when the remote references are unreachable is misbehaving.
There is no need to add yet another GPS receiver, for the purposes of the standard linux machines clock time (not the Virgo data frames time) It should be enough to use properly local hardware clocks.
We are going to check the windows domain servers time synchronization configuration in order to handle this corner case correctly.
This morning we continued the sanity check of the ALS beam at the ends. We started checking the status of the ALS fibers at the WE,without finding any particular issue. However, the IR power coming from the fiber was still too low to seed the amplifier.
We then went in the DAQ room were the pickoff fiber arriving from EIB is then 50:50 splitted in two beam for north and west end. At the input of the splitter, there was another fiber splitter (90:10, see fig. 1), used in the past to reduce the power without affecting the phase camera and squeezing pickoffs. As the ALS pickoff is now indipendent from the others, we decided to remove it. As a result, the infrared beam was powerfull enough to close both WARM and NARM pstab and to seed both amplifier.
Moreover, we noticed that the ALS CEB green power was also quite low (<10mW), indicating a misalignment of the beam on EIB, most probably due to the work on the BPL/BPC loops of the last weeks.
A realignment of the green beam on EIB will be done in the next days.
ITF DOWN in UPGRADING mode.
Planned activities:
- 06:30 UTC - NI Cryotrap valve open. Laser beam on north arm.
- 14:30 UTC - WI Cryotrap valve open. Laser beam on west arm.
- North arm alignment (still in progress...)
06:30 UTC - NI Cryotrap valve open. Laser beam on north arm.
14:30 UTC - WI Cryotrap valve open. Laser beam on west arm.
Similar tests for studying acoustic modes of the laser bench room were made back in 2024 but with the HVAC on and no much effect was seen: https://logbook.virgo-gw.eu/virgo/?r=65126
The microphone added externally of the laser bench room is named ENV_CEB_LLR_MIC, the microphone insided the is named ENV_LLR_MIC.
In order to see the main laser beam on NE mirror and to re-align it, the pcal NE has been switched off on July 29 at 12:19 utc.
Pcal NE switched on on July 31 at 7:55 utc.
Before attempting the relock of the arms foreseen next days today I tried to asses the actuation balancing of the WI and NI payload at the level of the MAR, due to the new mounted payloads.
The coupling between Z corr and TY corr have been evaluated through some DC steps applied in Z corr, in order to compute the correct driving weigths to minimize such coupling. Both for NI and WI the misbalancing was quite high.
For WI the found value was 0.0046 (from 0.0002), directly applied in the branch that feeds part of the Z corr in TY MAR corr, see Fig.1. Further fine tuning are not appreciable since we are covered by corr signal noise.
Once we have a lock, by measuring some TF between the corrections, it will be easier to estimate the finer weights.
For NI the found value was quite high with respect to the current one, but I didn't implemented it since for NI is not possible to see at a first sights the effect of the driving adjustment due to the way the corr probes are implemented in the DSP card. So I will leave it for tomorrow.
Same decoupling procedure has been applied also to minimize z2roll coupling z-> tz corr, fig.2. (WI weight: from 0.0115 to 0.0104; NI weigth: from 0.00374 to -0.01326)
N.B. MIR coil balancing both for NI and WI need yet to be done.
Motivation: the first scope is to study the sound transmission between the CEB hall and the two labs: in order to quantify the contribution from the CEB HVACs this time we first switch off the INJ and DET labs HVAC and THEN the hall and CleanRooms HVACs. Also, we perform a white noise injection with one of the two sub-woofer positioned in the DET terrace. The second purpose is to study the origin of the low frequency peaks at approximately 12 Hz and 19 Hz which are clearly seen by microphones when the INJ HVAC is off (previous investigations: elog https://logbook.virgo-gw.eu/virgo/?r=69148).
Preparation (this morning):
Action times:
The laser lab temperature increased by 1deg overall as shown in Figure 2. The weather conditions were good, with low wind (also in Fig.2). Analyses will follow.
Similar tests for studying acoustic modes of the laser bench room were made back in 2024 but with the HVAC on and no much effect was seen: https://logbook.virgo-gw.eu/virgo/?r=65126
The microphone added externally of the laser bench room is named ENV_CEB_LLR_MIC, the microphone insided the is named ENV_LLR_MIC.
We had a look to the effect of the sound wave pulses produced by repeated door opening and closing.
In the morning, while the HVAC was on, we performed a set of pulses with the door between the laser bench room and the minitower room. Figure 1 shows ASD of the microphones inside the laser bench room. They all see a bump at approximately 20Hz growing above the noise backround noise. We remind that the "LLR" microphone was positioned in the N-W corner of the room, at aproximately the beam height.
In the afternoon we repeated the same test, but the HVAC was off (also those of CEB) and we acted with the door between the Atrium and the laser bench. In Figure 2 (and Fig.3) the purple spectra correspond to the quiet condition. Two bumpy structures at approximately 12 Hz and 18.5 Hz are visible, in particular in the LLR microphone. In the excited condition (blue) microphones see again a peak at about 20Hz and also, less pronounced, growing bumps at roughly 40, 45, 55, 85,135 Hz (Figure 2).
Figure 4 (also 5 and 6) is a spectrogram of LLR mic over the time of this test. After the test is finished (about 13:13:30 UTC) additional pulses around 20Hz are seen (actually here the excited frequency is a bit lower, it looks more around 18.5Hz). These are due to Irene exiting the lab and opening/closing the doors of the atrium, the SAS and the piscina.
We would interpret these frequencies as acoustic modes of the room. We are also tempted to think that the 18.5 Hz bump seen in quiet condition is the same 20Hz mode excited by the door. We have excluded already it to be a resonant mode of the air ducts ( https://logbook.virgo-gw.eu/virgo/?r=69148). The frequency mismatch (20Hz instead of 18.5Hz) however needs an explanation.
The attached shows the excitation produced by opening and closing the doors of the SAS and piscina. The excited bump looks well matched to the 18.50 Hz one. Some small excitation of the 12Hz bump is noticeable as well.
As rotors were moved, the hInj values change.
All values have been updated in NCalMoni.cfg, /virgoData/NCal/set_NEB_default_lines.sh and /virgoData/NCal/set_WEB_default_lines.sh. after new fromage simulation.
Values will need some more tuning as:
-WEB mirror position needs to be determined
-NEB rotor survey was not complete
