- Extraction of WI payload Monday 18/5
- Suspension of NI Mirror to the marionette 22/5
- integration of NI paylaod into the NI tower 23 or more reasonably 25/5 + 1 day to VAC
- Suspension of WI Nirror to the marionette 3/6
- Integration of WI paylaod into the NI tower 6/6 + 2 days to VAC
The seed planning will be modified according to this outline pivoting on VAC and TCS availability.
Today, after the dismountling of the two baffles in front of the mirror (HR side) by L. Naticchioni e M. Ricci, I applied First Contact on the payload HR surface.
Before applying the FC, I inspected a bit the surface and I could spot many dust particles (Figs. 1 to 2). I could also find a big scratch on the upper left side of the mirror (Fig. 3). Moreover, it was possible to observe by eye the big point absorber found previously with the thermocamera (VIR-0106A-26) roughly at 9 cm to the right wr.t. the center of the mirror (Fig. 4). Measuring it on the picture, a slight more precise estimation is 8 cm, instead of 9 cm.
Figs. 5 to 7 show the FC application process and the completed work.
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- front straylight baffle dismounted => work by Suzanne
- electrical check by Yuri on the RH mount after the extraction of the CP mount done yesterday)
- gradual disassembling of the paylaod
- mirror brought into the Cl.1 hood
- careful cleaning of the various parts of the payload (fused silica dust and small pieces of glass)
- readjustment of the marionette position into the cage (preparation to the suspension operations)
further preparatory Crosschecks
- magnets ready for the HCB for both NI and WI
- steel plates lambda/10 polished to HCB the upper anchors ready, for both NI and WI
In Fig 1: dismounting the parts (in the background the RH mounts
In Fig.2: the various parts into the Cl1. hood. You notice the present CP into its round mount set in vertical., the dismounted mirror, and the box with the spare NI mirror that will be assembled into the paylaod. The two spare CPs are also seen into their boxes (the new ears under HCB hardening can be also noticed)
Precious the collaboration of Buggiani and Bazzi, with the prompt help provided under our request.
- Extraction of WI payload Monday 18/5
- Suspension of NI Mirror to the marionette 22/5
- integration of NI paylaod into the NI tower 23 or more reasonably 25/5 + 1 day to VAC
- Suspension of WI Nirror to the marionette 3/6
- Integration of WI paylaod into the NI tower 6/6 + 2 days to VAC
The seed planning will be modified according to this outline pivoting on VAC and TCS availability.
ITF found in UPGRADING Mode and DOWN State.
All times are UTC.
06:57 TCS Chillers refill (Ciardelli).
08:21 West arm large valves opened (Vacuum team).
From 09:02 to 09:07 TCS WI CO2 Power Checks (Operator).
From 09:26 to 09:29 TCS WI Thermal Camera References (Operator).
During the shift the West Arm IR was recovered and ALS green was checked (Spinicelli, Pinto, Casanueva, De Rossi, see #69072).
ITF left in UPGRADING Mode and DOWN State, measurements on the PR suspension ongoing (Boschi).
TCS WI CO2 Power Checks:
| CH [W] | INNER DAS [W] | OUTER DAS [W] | ||
| WI | on the pickoff | 0.419 | 0.025 | 0.249 |
Today we have checked the green lock after the installation of the source in the EIB bench. The motivation of this action was to reduce the amount of fiber used in the propagation of the green, since the air conditioning in the Laser Lab was producing noise that was strongly polluting the error signals.
We first aligned the west arm and locked the infrared without major problems. Then we locked the green in reflection of the west arm, which locked without major problems as well. At this point we checked the signals seen by the PDs in teh central building (ALS CEB WARM BEAT 154MHz). There is no saturation, we have slightly improved the "mag", and the spectrum of the error signal that we used (_dFreq) has improved a lot at high frequencies where we were dominated by the air conditioning noise (see Figure 1). The rms has improved by a factor 4 (our-of-loop).
We will have to wait to have both arms to check the passage to CARM/DARM but the target will be to increase the UGF of these loops. In order to check that we are no longer limited by the ambient noise we will make a test of turning off the air conditioning.
After the successfull deploiement for the WEB NCAL , we continue to use this new firmware on WEB and NEB PCal system and for the NEB NCal one.
Below the list of the operations performed:
- WEB PCAL system
- Update the DAC1955-SN11 (WEB_PCAL_DAC) located in the DBOX-SN49 with the v3r3 release for the FPGA firmware and the DSP code
- Update the WEB_PCal_fast Acl server
- Update the WEB_PCAL_DAC part in the SWEB_dbox_rack DBox server and reconfigure it
- After these operations the WEB_PCAL loop was successfully close
- operations performed between 2026-05-05-06h49m50-UTC and 2026-05-05-07h27m54-UTC
- NEB NCAL and PCAL systems update
- Update the VPM Online configuration to use the DaqBox v17r9 for the SNEB_dbox_{bench,rack} servers
- Update the DAC1955_SN6 (NEB_DAC_NCAL0) ) located in the DBOX-SN118 with the v3r3 release for the FPGA firmware and the DSP code
- Update the DAC1955_SN18 (NEB_DAC_NCAL_TCS) located in the DBOX-SN119 with the v3r3 release for the FPGA firmware and the DSP code
- Update the DAC1955_SN121 (NEB_DAC_PCAL) located in the DBOX-SN35 with the v3r3 release for the FPGA firmware and the DSP code
- Update the NEB_NCal server configuration
- Update the NEB_PCal server configuration and the NEB_NNC_Tilt server configuration
- these 2 servers are sharing the same DAC1955_SN121 (NEB_DAC_PCAL) but each one sends a Tolm packet related to its used channels
- Update the SNEB_dbox_rack configuration to set the related DAC1955 boards configuration
- operations performed between 2026-05-05-08h28m20-UTC and 2026-05-05-09h39m12-UTC
- After these operations only the NEB NCAL loops were tested and all were successfully closed
- for the NEB_rtpc, the output data flow related to the DAC1955 boards was reduced from 29.4MB/s to 19.3MB/s
After the removal of the NI payload from the tower and its transfer to the Clean Room in CB, I applied First Contact to the AR side of the mirror (the CP and the rear baffle was dismounted and separated from the payload). Tomorrow morning (05/05/26) a second application in the HR face is planned.
Today, after the dismountling of the two baffles in front of the mirror (HR side) by L. Naticchioni e M. Ricci, I applied First Contact on the payload HR surface.
Before applying the FC, I inspected a bit the surface and I could spot many dust particles (Figs. 1 to 2). I could also find a big scratch on the upper left side of the mirror (Fig. 3). Moreover, it was possible to observe by eye the big point absorber found previously with the thermocamera (VIR-0106A-26) roughly at 9 cm to the right wr.t. the center of the mirror (Fig. 4). Measuring it on the picture, a slight more precise estimation is 8 cm, instead of 9 cm.
Figs. 5 to 7 show the FC application process and the completed work.
We starter with the NI.
1) removal of the safety frame at the sides of the payload, they have been located in the underground clean area close to the ITM towers;
2) removal of the HWS mirrors with the related mounts. They have been wrapped and located in the clean area under the detection port, see Fig. 1;
3) we took some pictures and we started noticing that the X stops of the CP were properly set not to touch the plate, Fig 2;
4) we were then about to block the marionette on the cage, in order to start the extraction operation but before touching anything (neither the cage nor the suspended bodies marionette and mirror), we heard a sharp noise. What happened was clear as we saw the vertical stops above the marionette, they were touching, a clear sign of an upwards jump due to fiber breaking. These fibers worked with honor for more than 8 years (Fig. 3)
5) After a crosscheck of the mirror position, quite rotated due to the fact that only two fibers, both on the W side got broken, there was nothing to do than proceeding with the standard maneuvers to extract the payload (Fig 4 and 5).
6) Then the payload, thanks to the valuable efforts of the VAC crew was brought upstairs into the clean room, ans seated on the assembling table.
7) The mounts of the CP and RH were dismounted (Fig. 6)
8) And finally the main mount of the CP, with the CP inside, was separated and set into the clean hood in class 1.
We have re-verified the angular and longitudinal WPs after the work of today.
The new values of the angular WP are close to zero but the horizontal FF. We will investigate the reason for this difference in the following days.
NF H: -0.02
NF V: -0.075
FF H: -0.62
FF V: -0.05
Instead the longitudinal WP remained quite large as measured last week (-1.7V).
Last Thursday a large longitudinal working point offset was observed in the IMC locking loop. In addition, the RF QPD in near field used for IMC alignment did not appear to behave correctly.
Given the significant mode mismatch previously measured (~13%), we redistributed the power by reducing the PMC input by 20% and compensating with IPC1, with the aim of modifying the thermal lens in the EOM and Faraday. Following this change, the mismatch improved to ~9%.
In parallel, a peak at 0.8 Hz was identified in the RF QPD spectra. Maria and Irene performed a Bruco analysis and found coherence with MC TY, suggesting that the feature originates from the AA matrix.
We then optimized the IMC alignment and remeasured the sensing matrix. The 0.8 Hz peak on the horizontal signals was significantly reduced (see comparison plot between Apr 10, this morning before power reduction, and now). However, the longitudinal working point remains large and comparable to last week. Checks of the 22 MHz signal and the RF photodiode after the EOM (EOM_EAB_TRA) do not show any increase in amplitude modulation, leaving this effect unexplained.
To further investigate the mode mismatch, beam profile measurements were performed on EIB after M5 under two thermal conditions: current configuration and with PMC_TRA increased by 20% (as earlier this morning). The goal was to identify possible thermal lensing, including its position and focal length.
Measurements (around 17:17 LT, low PMC power, 29.6 W after EIB M5, IPC1 = -54250 step, ~4.4 mW sampled after M5) :
z from M5 (mm) ellipticity beam width (um)
85 97 1280 um
135 98% 1290
185 100 1380
235 100 1420
285 1470
335 1480 (1530)
After increasing PMC_TRA by 20% (17:24 LT, ~5.3 mW sampled),
85mm 97% 1260
135 98 1305
185 99 1360
235 97 1405
285 96-97 1490
335 98 1520
The measurement sequence ended at 17:37 LT, and the system was returned to low PMC power at 17:44 LT (IPC1 = -51500).
A preliminary analysis of the beam profiles indicates a waist of ~508 µm located at -0.49 mm from M5 in the low-power case, and ~444 µm at the same position in the high-power case (+20%). Using the known waist at the output of the LB (639 µm at 13 cm from EIB), these results can be reproduced by introducing a thermal lens in the third EOM with a focal length of ~1090 mm (low power) and ~900 mm (high power). The variation in focal length is consistent with a linear dependence on absorbed power. Quantitatively, this would correspond to an effective absorption on the order of ~2000 ppm, significantly larger than the expected 50 ppm/cm for a 20 mm crystal.To be followed.
Additional activity :
Realignment and calibration of EIB POUT : 34.5 W on the channel with 0.485 PMC_TRA_DC while 29.6 W have been measured.
We have re-verified the angular and longitudinal WPs after the work of today.
The new values of the angular WP are close to zero but the horizontal FF. We will investigate the reason for this difference in the following days.
NF H: -0.02
NF V: -0.075
FF H: -0.62
FF V: -0.05
Instead the longitudinal WP remained quite large as measured last week (-1.7V).
This afternoon we put in operation the DAC1955 v3r3 firmware for the NCAL WE . After the upgrade; the WEB NCAL loops, frequency and phase, were successfully closed.
Below the details of the operations:
- use DaqBox v17r9 version for the WEB rtpc DaqBox servers
- update the DAC1955 SN53 (DBox SN121) and DAC1955 SN73 (DBox SN 175) firmware qnd DSP code with the v3r3 release
- The DAC1955 chips are now running at 400KHz instead of 100KHz previously, with an analog anti-image filter cut-off unchanged at 20KHz
- update the SWEB_dbox_rack configuration and the WEB_NCal one
- operations complete at 2026-05-04-14h46m00-UTC
ITF found in down and in Upgrading mode.
Below the list of the activities communicatd in control room:
- NI payload intervention; in progress.
- Instrumented baffles installation; in progress.
Cal
At around 11:30 UTC Alain started to work at WE Pcal.
Susp
At 12:34 UTC we had a problem with the DSP BPC board. I contacted Valerio and he fixed the problem performing the download of the code.
SBE
The DMS was reporting that SPRB_SBE vertical correction was close to saturation; I recovered it using the stepper motors.
The spare part has been installed and then the pumpdown was started. The cryotrap is now under high vacuum, and the cooldown is foreseen from next tuesday.
A few more observations concerning the test of April 23:
- at some point, while the AHU was off, we stopped the water flux by closing the valves located inside the CEB AHU room. Unespectly we measured an increased acoustic noise in the range 50 to 100 Hz (Figure 1)
- between 8:49 and 11:13 UTC, while the AHU was off, we closed all air valves of ducts (all set to 0%). In principle we would expect some change in the position of low frequency spectral peaks, if they were associated to acoustic modes of the air ducts. We did not notice any change (Figure 2).
- acoustic spectrograms show some peaks changing frequency, mostly above a few hundred Hz. They seem correlated to the frequency of the SUPPLY fan (Figures 3 and 4). Yet, we then notice that similar ones are present also when the HVAC was running in MANUAL modes (that is when both fans frequency fixed): Figure 5. Could they be associated to the air flow regulators instead?
- IMC alignment and measurement of the new AA sensing matrix
- IMC longitudinal wp. The offset on the IMC PDH error signal appears to be quite large (-1.6 V, see attached plot). However, with this offset the IMC lock is very unstable, so we left the old one -0.07 V. To be understood why the scan gives such large offset (maybe on monday we will check the alignment in the EOM? on the IMC refl photodiode?)
- IMC Fmoderr. We made it with the automation and it was very close to the optimal wp
- IMC angular wp --> we found an issue on the NF V RF quadrant. We did the usual scans of the galvo working points (scanning the offsets of the galvos) and look at the coupling between error signal and frequency noise (TF between perturb at 1111Hz and the Quadrant signal (the demodulated quadrature I). We observed a strange behaviour for te NF V (non linearity: changes slope around the 0). See plots 2 and 3 which compare current scan (30 Apr 13:17:02 UTC) with an old one (10 Apr 2026 10:03:10 UTC): the magnitude doesn't go to zero and the phase behaviour looks strange. We then went in the LL Atrium and unpowered and powered again the NF QPD electronic box and made another scan at utc2gps(2026,04,30,15,05,08) from -0.5 to 0.5 in 300s (plot 6 and 7), which was still bad. To be investigated next week.
- IMC OLTF we found 96 kHz UGF and 30 deg phase margin. We added 1 dB to get 107 kHz and 23 deg phase margin (plot 8)
In the meanwhile we prepared the Acl code ISYS_BPL for the bench pointing loop. We still have to plug the PZTs to the DAC (we need prior to find a solution to block the beam before the EOMs while testing the PZTs, since the risk would be to burn something)
Here attached some pictures of the EIB after the installation.
Since yesterday 12:00 LT (April 29) the DET AHU is running in MANUAL mode (fixed fan frequencies) at slightly reduced rate of the SUPPLY fan (28.5 Hz instead of usual 31.5). Ambient parameters (TE, HU, PRES) look stable enough (see attached) so we decide to keep it in this configuration untill Monday.
ITF in DOWN, UPGRADING
This morning the INJ team worked on beam realignment and RFC locking. The MC valve was opened by the vacuum group.
After the operations in laser lab, hvac pressure system working point was set back to normal and BACnetServer was restarted.
At 12:00 UTC the vacuum group started venting NI tower
- today upgraded versions of the quadrant photodiodes for the bench pointing loop have been installed. In fact yesterday Piernicola and Flavio found out that the excess of noise on the QPD signals was probably due to the length of the cables.
The two QPDs have then been realigned to have DC and asymmetries close to 0 (plot 1) and plot 2 shows the noise of the QPDs without any laser beam.
- In order to close the BPC we had to move the picomotors on M6 and M8 mirrors on EIB. We found that the driver for the M8 tx ty picomotors doesn't work anymore. We temporarly plugged M8 tx and ty on Far M1 ty an tx respectively. We could then close the loop
- we finally struggled to lock the IMC since we had not realized that the valve between SIB1 and MC had been closed (we thought the beam was misaligned instead).
Tomorrow we will continue with the INJ recovery and precommission of the quadrants on EIB.
*** Erratum ***
Due to an offset between the Kieback & Peter interface and the inverter, the supply and return fan speeds reported were incorrect.
The values in the table below have been updated, and an additional frequency step has been added.
| Time | Mode | Supply fan frequency | Return fan frequency | Note |
| April 27, 12:30 UTC | Automatic | ~32 Hz | ~13.8 Hz | Supply: air speed ~2.6m/s → Air flux~3276 m³/h Return: air speed ~0.2 m/s → Air flux~252 m³/h |
| April 27, 16:10 UTC | Manual | ~22 Hz | ~15.7 Hz | Supply: air speed ~2.5m/s → Air flux~3150 m³/h Return: air speed ~0.3 m/s → Air flux~378 m³/h |
| April 28, 09:40 UTC | Automatic | ~32.8 Hz | ~13.8 Hz | |
| April 28, 15:00 UTC | Manual | ~22 Hz | ~15.7 Hz | |
| April 29, 10:36 UTC | Manual | ~28.5 Hz | ~13.8 Hz | Supply: air speed ~3m/s → Air flux~3780 m³/h Return: air speed ~0.3 m/s → Air flux~378 m³/h |
ITF found DOWN in UPGRADING mode.
he planned activity on Free space ALS / LB->EIB pointing went on for the whole shift.
Software
13:10 UTC: SUSP_Fb restarted after a crash
In order to debug the new QPDs installed for the BPL loop, which show anomalous noise in both DC and asymmetries signals, we removed from EIB bench one of the new QPD (SN: DCQPD26-1) and from EAB bench the QPD used for IBJM (SN: DCQPD 4).
For the time being, EIB bench is blocked and the PMC in scan with the beam blocked on LB.
In the table below are reported the latest actions performed on the supply and return fan operation.
| Time | Mode | Supply fan frequency | Return fan frequency | Note |
| April 27, 12:30 UTC | Automatic | ~32 Hz | ~13.8 Hz | Supply: air speed ~2.6m/s → Air flux~3276 m³/h Return: air speed ~0.2 m/s → Air flux~252 m³/h |
| April 27, 16:10 UTC | Manual | ~28.5 Hz | ~13.8 Hz | Supply: air speed ~2.5m/s → Air flux~3150 m³/h Return: air speed ~0.3 m/s → Air flux~378 m³/h |
| April 28, 09:40 UTC | Automatic | ~32.8 Hz | ~13.8 Hz | |
| April 28, 15:00 UTC | Manual | ~28.5 Hz | ~13.8 Hz |
In Figure 1, a slight temperature drift of approximately 0.1–0.2 °C is observed over time, together with oscillatory behavior in the humidity control loop.
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