After the completion of the SDB1 tower evacuation, the VAC team opened the BS-SR and DET cryotrap valves to send the NI single bounce beam towards SDB1. Meanwhile Paolo restored the reference position of the SDB1 bench in vacuum and closed the position loops. Henk-Jan restored the nominal height of SDB2 and could then close the position loops.

We adjust the SDB1 angular setpoints in order to center the beam on the B1p camera (Fig.1): This was achieved by setting TX = 70 and TY = 80 urad

Noticing that the TX correction is around -4V, we acted on the BENCH_TX motorized counter-weight with -16000 steps in order to reduce this correction around -0.4V. Adding this to the steps performed last week, the motorized counter-weight is now off-centered in TX by -50000 steps.

We adjust the OMC Peltier gain (from 20 to 50) in order to be able to control the OMC temperature in vacuum. OMC temperature stabilization loop closed at 13h46 utc.

We close B5 beam drift control at 13h50 utc. The position of the B5 and B1p beam on their cameras with the B5 drift control closed are shown on Fig.2 and Fig.3

Open OMC shutter at 13h56 utc. We check that in these conditions, the B1s beam is almost perfectly centered on the camera (Fig.4). The powers obtained on the photodiodes are shown in Fig.5. In particular we have 78 mW on B1p and 93 mW on B1s.

We start an OMC lock acquisition at 14h18 utc starting from 22.45 deg. We observe a mode of order 5. Therefore we stop the scan and adjust manually the OMC temperature to 22.54 deg. Start another scan for OMC lock acquisition at 14h23m50. The OMC is properly locked around 14h30 utc (Fig.6) with about 12.8 uW on B1_PD3.

We improved the alignment of the OMC in TX and achieve about 14.8 uW on B1_PD3 (Fig. 7).

Start OMC scan at 14h57 utc

Order 1: 1.1 uW > 7% of misalignment defect

Order 2: 0.2 uW > 1.4% of mode mismatch

We update the picomotors names as follows:

* Old "B5_M2_H" / "B5_M2_V" becomes now : "B5_M1_H" / "B5_M1_V"

* Old "B5_M1_H" / "B5_M1_V", becomes now: "B1s_M3_H" / "B1s_M3_V"

We then try to close the SDB2 galvo loops. All loops were closed at first attempt except the galvo of B5_QD2 (the new B1s QPD). In order to recenter the beam on the quadrant we acted on the mirror B1s_M3 with the following steps:

B1s_M3_H -1200 steps

B1s_M3_V +1200 steps

Then the B5_QD2 galvo loops was closed successfully.

We also acted on B1p_M1 and B1p_M2 to reduce a bit the vertical corrections (B1p M2 V +400, B1p_M1_V +300)

Fig. 8 shows all galvo loops closed with small level of corrections.

We open all galvo loops at 15h34 utc.

Scan SDB2 bench in TY (Fig.9): We can see that for the nominal setpoint of the bench TY = 880 urad the B1p photodiodes are well centered and during the scan the beam is always inside B1s. For B5, TY=880 corresponds to a maximum, but it is very close to the edge of the power plateau. This behaviour is probably due to the fact that the photodiode is seeing a second beam in addition to the main beam (as on B5 camera) when the main beam is close to being clipped. We decided to adjust the centering of the B5_PD2 photodiode (acting on B5_M3 and B5_M4 picomotors) in order to better center the main beam for TY=880 urad. While repeating the TY scan of the bench, we obtain Fig.10. We intentionally kept the B5p photodiodel on a maximum for TY=880, but it is not clear if that is the best tuning. We leave it as it is for now.

Fig.11 shows a small scan in TX which does not have any impact on the photodiodes power.

We conclude here the alignement checks.

Close OMC shutter at 16h55 utc.

At the end of the shift we restore the SDB1 floating setpoints. Then we open the B5 beam drift control and restore the B5 QD offsets used in dark fringe.

We started the activity at approximately 13:50 UTC (69638), following the steps described in issue #186 for the inner ring checks:

• Installed SPIRICON 1 at the CINOGY position, using the available bench marker.

• Verified that the power in the DAS IN branch was already set to its minimum, as required to follow the beam along the CINOGY telescope path.

• Checked the intensity distribution of the inner ring.

• A vertical asymmetry and a smaller horizontal asymmetry were observed. We therefore adjusted L3_tras to recover a more uniform intensity distribution. Figure 1 shows the inner-ring profiles before and after the adjustment.

The activity ended at approximately 16:15 UTC. The WI CO2 bench was secured, and the white curtains were closed (69639).

The checks will continue tomorrow, after the maintenance work has been completed, with the outer ring measurements.

Activities on the WI CO2 bench have finished for today. The enclosure and the white curtains were closed at approximately 16:15 UTC.

Activities will resume tomorrow after the maintenance work has been completed.

6:00 UTC DET lab air flow set back to REDUCED ("Portata Ridotta") (operator)

8:30 UTC INJ alignment (Gosselin, Lagabbe)

9:00 UTC Unblocking of SQZ beams towards SQB1 (Sorrentino)

12:00 UTC BS-SR valve opening (Vacuum Team)

13:00 UTC SDB1 position loops closed, SDB2 and SPRB vertical position adjusted (Bulten, Ruggi, operator)

13:30 UTC TCS WI bench assessment (Lumaca, Corubolo)

Around 13.50 UTC, we are starting the check activities on the WI CO2 bench.

This morning around 9:20 UTC I removed the beam dumps from EQB1.

This afternoon, we went back to the detection tower to check the position of the motorized counter weight (on which we performed -34000 steps yesterday evening). We observed that the translation stage is about 0.5 mm from its zero position, which we considered reasonable.

Fig.1 shows the values of the angular corrections applied on the marionetta.

We then gave green light to the VAC team for the closing and evacuation of the SDB1 tower. We opened the angular control and the OMC temperature stabilization loop.

While checking with the operator the status of the position loops we realized that we had forgotten to close them in the morning. On Fig.2 we check the evolution of the SDB1 bench position between yesterday morning when we took the alignment reference (around 10h00-11h00 utc) and the position of today. We can see that they are very similar despite the fact that the loops were not closed today.

Since we could not replug the B5_M1_TX picomotor on SDB1, we have unpluged the cable from the picomotor driver 8742 SN 10592, channel 4. The cable is left free, we have attached a sticker on it with the label "B5_M1_TX".

The beam dump that was placed on the reference beam path of the B1p PC on August 13th has now been removed. The beam dump is stored inside the rack of the DET lab.

ITF found in SINGLE_BOUNCE_NI (with PR misaligned about 30 urad in ty), in COMMISSIONING mode.

planned activty:
- SDB1 intervention (Gouaty, Romero). Activity concluded at 14:30 UTC.
- 11:30 UTC Melo in Laser Lab to block the beam in order to allow Bulten to work on the eccess of noise on EIB.

SBE
11:30 UTC - SIB2_SBE loop opened for unknown reason. Properly closed via VPM. Unfortunately the loop opened again after 10 min. I contacted Bulten who fixed it at 12:15 UTC.

Around 11:30h UTC I went to the LL and blocked the beam at the output of LB to allow works on the EIB for the excess noise found since last Friday (see #69600). BPC loop is open and INJ node in metatron is in down and paused. 

WE WRITE AND POST THIS ENTRY A SECOND TIME SINCE IT WAS ERASED FROM THE LOGBOOK AFTER OUR FIRST ATTEMPT.

This morning we performed another round of alignment checks after the intervention in SDB1. 

Air flux is off, BS-SR valve open to let the NI single bounce beam reach the SDB1 bench, nitrogen blowing on the cryotrap window.

The suspension control of SDB1 were restored by Paolo yesterday night. SDB1 angular control are closed.

Noticing that the height of SBD2 has drifted away during the night, we remove a few temporary weights to adjut the bench height close to 500 um. Then we close SDB2 angular and position loops.

We then check the position of the beam on B1p camera. it is too high. Thefefore we change the SDB1 angular setpoints to recenter it : in TX setpoint changed from 60 to 15 um, in TY setpoints changed from 20 to 27 um. After this adjustment we checked the position of the B1s beam on the silicon beam dump on SBD2 (using an IR card) and it was found well inside the beam dump.

We open the OMC shutter and check that the B1s beam is well centered in its camera (Fig.1). Initially we read a power of about 40 mW on B1s (Fig.2). Then we checked that the B1s beam is still passing through the iris placed at the input of the EDB bench.

We performed an OMC scan and found the following powers per mode:

• TEM00 mode: containing a power of 1uW (see Figs. 3 and 4)
• 1st HOM: containing a power of 2uW (see Fig. 5 and 6)
• 2nd HOM: containing a power of 1.8uW (see Fig. 7 and 8)
• 3rd HOM: containing a power of 2uW (see Fig. 8 and 9)
• 4th HOM: containing a power of 2uW (see Fig. 10 and 11)
• 5th HOM: containing a power of 2uW (see Fig. 12 and 13 )

This makes a total of 10.8uW. Assuming a calibration factor of 4800 on B1_PD3, we get a total power of 52mW, compared to the B1s power of about 70mW.

We check that the B1p, B1s and B5 galvo loops centering is working well (Fig.14). In order to be able to close the B5_QD1 galvo loop we had to perform a little adjustment (order of 1500 counts) with the picomotors B5_M2. REMEMBER TO UPDATE THE NAMES OF THE PICOMOTORS WHICH ARE NOW VERY CONFUSING (B5_M1 for B5_QD2 now on the B1s beam, versus B5_M2 for B5_QD1).

This concluded our alignment check.

We close the OMC shutter, open the SDB2 local controls. Remove SDB2 temporary weights, remove EDB irises.

We close the SDB2 vacuum chamber and starts the pumping around 10h30 utc.

We ask the VAC team to close the BS-SR valve as we do not need the laser hazard in DET tower any more. The air flux in the tower is switched back on. We close the nitrogen bottle.

We inform the Laser Safety Officer that laser hazard it not needed any more inside the DET tower.

After the daily meeting we started the intervention in SDB1.

After switching off the laser; we entered the tower and started by blocking SDB1. Then, we inspected the bench. We did not notice any anomaly. Hence, we proceeded with the closing and  reopening of the fast shutter after verifying the blades were ok.

We then removed the waveplates and their corresponding clamp and screw (539g). We did not remove the beam dump placed in reflection of the waveplate. To be noted that we did not replug the cable that was used for the waveplate (as there was not easy access to recable it to the B5_M1_TX picomotor).

We then unplugged the OMC shutter translation stage. We dismounted the translation stage and replaced it with the spare one. We repluged it and tested successfully.

We add 540 g of weight under the bench to compensate for the weight of the withdrawn waveplate.

We recenter the motorized weight manually.

We then rebalanced the bench and left the detection tower.

However, we noticed in the control room that the TX position has drifted away a bit and the loop could not be closed any more. To fix this we performed -34000 steps with the BENCH_TX motorized counter-weight. We could then close the angular loops as shown on the attached Figure. We notice large fluctuations in TX and TY (+/-10 urad). This may be due to the presence of the air flux in the tower and maybe the thunderstorm.

We leave the tower slightly open, with nitrogen off, and air flow blowing.

Tomorrow, after the recovery of the suspension control, we will perform an alignment verification.

ITF found in COMMISSIONING Mode and DOWN state, with MISALIGNED_ALL_BUT_NI state on ARMS_LOCK node (equal to SINGLE_BOUNCE_NI state from ITF_LOCK)

7:30 UTC OB Top Stage loops opened (operator), DAQ reconfiguration (Masserot), Closing of BS-SR valve (Pasqualetti), SDB1 rack cables swapping (Gouaty, Romero)

8:00 UTC Opening of SDB1 tower bottom flange, hood with nitrogen flow installation on cryotrap viewport (Vacuum team)

8:12 UTC SDB2 LC troubleshooting and rebalancing (Gouaty, Romero)

9:30 UTC Opening of SR-BS valve (Pasqualetti)

12:00 UTC INJ troubleshooting on EIB (Gosselin, Melo, Ruggi)

12:30 UTC Closing of SR-BS valve (Pasqualetti)

13:00 UTC entering SDB1 tower to change OMC shutter traslation stage (Gouaty, Romero, Menzione)

At 14:00 LT, we went into the LL to perform a more detailed inspection of the EIB bench. We first put the beam in scan mode and blocked it at the LB output.

We then opened the bench controls and slightly moved the plexiglass tube leading to the SIB1 tower, as it appeared to be in slight contact with the bench. However, a comparison of the FFT signals before and after the intervention showed no significant change, suggesting that the contact was not the cause of the excess noise. No other obvious issues that could explain the increased noise were identified during the inspection.

We then unblocked the beam, re-locked the INJ system, and left the LL at approximately 14:40 LT.

Afterwards, we continued analysing the data. Paolo identified some LVDT signals, particularly the vertical 0 and 2 channels, that are significantly noisier than they were previously (see Fig. 1). A similar issue appears to have occurred in the past (see #57229), where the solution was to implement a low-pass filter to attenuate the excess noise.

It would therefore be useful to investigate whether this filter is still correctly implemented and functioning, or whether another issue is currently responsible for the additional LVDT noise.

Today, after the venting of the SDB1 tower was completed, the VAC team opened the SDB1 tower around 08h30 utc and installed the nitrogen setup blowing on the cryotrap window.

Meanwhile we performed some actions on the SDB1 rack:
➢ disconnect the SDB1 waveplate that we are going to remove from Agilis driver AG_UC8, channel 3 axis 2.
➢ Replug the cable on the picomotor driver 8742 SN 10592, channel 4 (B5_M1_TX)

The VPM main configuration has been updated accordingly to remove the button related the driving of the Pre-Faraday waveplate under SDB1_Rot process.

Noticing that the height of SDB2 bench had changed during the night, we went inside the DET lab to remove some mass from the bench and we were able to recover the right height, and to close the angular and position loops. However we lost the DAQ box LeftUp shorhtly after. So we had to reopen the control loops.

Paolo recovered the SDB1 bench position and the SDB1 local control could be closed.

We adjust the gain of the OMC Peltier to 20 (instead of 50) in order to be able to control the OMC in air. OMC temperature stabilization closed at 9h33 utc.

SDB2 control restored at 10h14 utc.

Antonio switch off the air flux inside the tower at 10h20 utc.

We take some alignment references with NI single bounce beam:

* SDB1 LC is set to TX = 60 (instead of previous WP at 120) / TY = 20 (instead of previous WP at 60)

* B1p camera is centered, with Pos X = -0.1, Pos Y = +0.15

We open the OMC shutter at 10h42m50 utc. We have 4 mW on the B1s beam. The beam is centered on B1s camera at position X = 0, Y = 0

To be noted that we observe an electronic offset of 31.2 mW on DET_B1p_DC when B1p_PD2 shutter is closed. We read 34 mW when the shutter is opened, which implies a power on B1p beam equal to about 3 mW which is in reasonable agreement with B1s power.

We open B1 PD1 and PD2 photodiodes at 10h52 utc.

We scan the OMC and observe the following modes:

* 0.1 mW on the TEM00

* 0.17 mW on the first order mode

* 0.3 mW on the second order mode

* 0.5 mW on the order 3

* 0.5 mW on the order 4

* 0.21 mW on the order 5

We close the OMC shutter, open the controls. Next step will be to perform the foreseen installation works inside the tower.

All the SDB2 DBoxes wer reconfigured but without any improvments . 

As trial the output of  the B5_QD1 and B5_QD2 demodulation  sample data were commented and  in these conditions , all the data were correctly received by the  SDB2_Photodiodes, SDB2_Quadrants and SDB2_Readout  servers.

To restore all the SDB2  demodulation sample data, for all the demodulation sample output packets  the output frequency is now set to 2kHz instead of 5kHz with 16 words of 32bits.