The ITF kept the Science mode for the whole shift. The Horizon had suffered some sporadic drops during the night.

Guard Tour
22:14 UTC - 22:43 UTC
0:11 UTC - 0:39 UTC
2:08 UTC - 2:39 UTC
4:06 UTC - 4:36 UTC

ITF found in Science Mode and kept the lock for the whole shift.
The Horizon had suffered a series of drops during the shift.

Guard Tours
17:32UTC - 18:06UTC
19:38UTC - 20:10UTC

A new commit of the DSP Code has been performed (revision 1314) and tagged as 'O3_4'. This version should be used for data acquired after May 13th at 10:07 UTC.

This morning I found the ITF locked, unfortunatly after a few minutes (at 5:15 UTC) the DMS showed that the temperature inside one crate at the NE (Daq_NEB_ADC_Moni1) was out of threshold (picture attacched). The ITF unlocked once at 05:38 UTC.

Downtime events

6:00 - 7:30 UTC / TROUBLESHOOTING MODE - I found a fan of the LAPP crate broken, therefore following the instructions of the expert oncall I exchanged the crate with a spare one, unfortunately the first spare that I took from the Central Building was not working, instead the second one worked fine and allowed me to replace successfully all the boards that have been not damaged from this failure. NB: no more working spare of this crate available on site.

Here the list of the TolmFrameBuilder where the event occured this morning

• Inj_Fb(rtpc2): 2019-05-19-06h00m57-UTC>ERROR..-[TolmFrameBuilderFrontEnd] Rtai DAQ FIFO overrun -> fifo is reset
• SIB2_Fb(rtpc7): 2019-05-19-06h00m47-UTC>ERROR..-[TolmFrameBuilderFrontEnd] Rtai DAQ FIFO overrun -> fifo is reset
• SDB2_Fb(rtpc7): 2019-05-19-06h00m42-UTC>ERROR..-[TolmFrameBuilderFrontEnd] Rtai DAQ FIFO overrun -> fifo is reset
• SNEB_Fb(rtpc8): 019-05-19-06h00m45-UTC>ERROR..-[TolmFrameBuilderFrontEnd] Rtai DAQ FIFO overrun -> fifo is reset

ITF found in Science mode. The lock was kept for the whole shift and survived an earthquake ( M 6.2 - 163km E of Tadine, New Caledonia ).
ITF left locked.

Guard Tour
13:42 UTC - 14:21 UTC
15:38 UTC - 16:13 UTC
17:41 UTC - 18:15 UTC
19:38 UTC - 20:14 UTC

ITF found in Science Mode.
At 06:00UTC, it unlocked as result of missing data, relocked at first attempt, Science Mode at 06:20UTC. The Horizon had suffered a series of drops during the shift.
ITF left in Science.

Guard Tours
05:10UTC - 05:37UTC
07:07UTC - 07:37UTC
09:32UTC - 10:01UTC
11:24UTC - 11:56UTC

ITF found in Commissioning Mode. The SQZ activity was concluded at 15:57 UTC (see entry #45918), after that I switched to Science Mode. The only interruption was from 19:33 UTC to 19:35 UTC, caused by the squeezer pump reset.
ITF left locked.

ACS
ACS DET switched to "Portata Nominale" from 14:12 UTC to 14:55 UTC to allow the alignment activity on the Squeezing Bench.

Guard Tour
15:07 UTC - 15:38 UTC
17:10 UTC - 17:43 UTC
19:16 UTC - 19:46 UTC

During this shift we perform a re-alignment of the squeezer and after that we measure the squeezing and anti squeezing level at different pump phase powers.

For eacg point we perform:

• a phase scan 240s of shot noise, 180 deg of phase scan with steps of 1deg and 3 seconds for each steps
• 10 minutes of squeezing injection
• 10 minutes of anti-squeezing injection

Point 1 (figure 1)

• OPA pump power = 1.9mW
• Sqz = -2.42 dB
• Asqz = 4.23 dB
• GPS shot noise: 1242206578
• GPS start scan: 1242206818
• GPS stop scan: 1242207372
• Sqz - Mag distance = -0.135 rad
• Dither demod phase = 5.2 rad
• Min mag phase = 0.92 rad
• SQZ phase = 0.8 rad
• Asqz_phase = 2.478 rad 
• SQZ GPS = 1242208221  18 May 2019 09:50:03 UTC
• ASQZ GPS = not performed (problem into OPO lock)

Point 2 (figure 2)

• OPA pump power = 2.8mW
• SQZ = -2.79 dB
• Asqz = 5.18 dB
• GPS shot noise: 1242209895
• GPS start scan: 1242210136
• GPS stop scan: 1242210690
• Sqz - Mag distance = -0.135 rad  
• Min mag phase = 0.89
• SQZ phase = 0.733 rad
• ASQZ Phase = 2.496 rad
• SQZ GPS = 1242211334  18 May 2019 10:41:56 UTC
• ASQZ GPS = 1242211990  18 May 2019 10:52:52 UTC
• End measurement = 1242212583  18 May 2019 11:02:45 UTC

From here we reduce the shot noise of each steps from 240s to 60, because before the scan the ITF was in low noise 3 thus the shot noise reference was automatically taken during the operation of the squeezer

Point 3 (figure 3)

• OPA pump power = 4.4mW
• Sqz = -2.96 dB
• Asqz = 6.68 dB
• GPS shot noise: 1242213670
• GPS start scan: 1242213730
• SQZ phase = 0.7854 rad
• ASQZ phase = 2.513 rad
• SQZ GPS = 1242214691  18 May 2019 11:37:53 UTC
• ASQZ GPS = 1242215435  18 May 2019 11:50:17 UTC
• End measurement = 1242216035  18 May 2019 12:00:17 UTC

Point 4 (figure 4)

• OPA pump power = 6.3mW
• Sqz = -3.25 dB
• Asqz = 8.46 dB
• GPS shot noise: 1242216765
• GPS start scan: 1242216825
• GPS stop scan: 1242217378.51
• Sqz - Mag distance = -0.228160360316577
• Min mag phase = 1.012 rad
• SQZ phase = 0.7854 rad
• ASQZ phase = 2.583 rad 
• SQZ GPS = 1242217846  18 May 2019 12:30:28 UTC
• ASQZ GPS = 1242218571  18 May 2019 12:42:33 UTC
• End measurement = 1242219172  18 May 2019 12:52:34 UTC

Analysis (figure 5): 

From the plot in figure 5 we can derive an optical loss for the squeezing of 30% and a phase noise which seems to be non-stationary but in the range between 120-150mrad. For the first three points a phase noise of 150mrad agreed well, for the 6.3mW pump power measurement a phase noise level of 120mrad fits better…This seems to be the main limitation for detecting higher squeezing levels at the moment.

After that we try to increase the squeezing level acting on the coherent control loop gain. We reduce it from 55 to 20, the RMS of the in loop and out of loop error signal was decreased (figure 6):

• In loop (B1 PD1): from 1.6e-4 V to 8.2e-5 V, i.e a factor 2
• Out of loop (B1 PD2): from 4.9 e-15 V 2.6e-15 V, i.e a factor 1.9

After that we reperform a phase scan (figure 7) but near the maximum of the anti-squeezing the CC loop oscillated:

• Shot noise:  1242220187.98 (4 mins)
• Phase scan:  1242220428.1

We found a squeezing level comparable to the previous, i.e. -3.25 dB, thus acting on the CC gain seem not useful to decrease the phase noise. 

After this work we performed other OPA alignment into the DET lab and finally we re-perform a phase scan

Final position (figure 8)

• Squeezing Level 3.0 dB
• Anti-squeezing Level 6.0 dB
• Squeezing phase = 0.3 rad
• CC loop slow set = 0.5e-3 V
• GPS phase scan: 1242227728 (4 min shot noise before)

Upon arrival, ITF was in Science Mode with HrecBNS ~48 Mpc
At 06:05 UTC started the planned SQZ activity on check of the alignment status.
In order to allow the activity, at 06:10 UTC, according with the crew, I:
1. exit from Science Mode
2. set Commissioning Mode
3. set ITF in Locked step
4. set True on sqz_debug line in ITF_LOCK.ini
5. put UTA DET in Portata Nominale
6. upon concluded the hardware activity in Det Lab (08:38 UTC) I put UTA DET again in Portata Ridotta.
7. set False on sqz_debug line in ITF_LOCK.ini
8. set again Low_Noise_3_SQZ
      points 3, 4, 7, 8 performed several times under request of the crew.

Activity in Control room on phase noise and loss budget started at 08:45 UTC and still in progress.

During the whole SQZ activity, ITF remained locked.

DMS / DetChar
at 08:47 UTC I stopped/restarted ITFOperationsDMS from VPM (Hrec_RANGE_BNS grey flag on DMS).

ITF found in Science Mode, it kept the lock for the whole shift. The Horizon had suffered a series of drops (see attached plot).
ITF left locked.

ISC
The ITF is locked with the BS AA in drift control and is still disabled also in the automation.

The ENV_NE Tiltmeter channls are correctly received by the SUSP_Fb TolmFrameBuilder since 

• 2019-05-14-09h07m56-UTC>INFO...-[TolmFrameBuilderSource::SetUp] New source ENV_NE (v1) with GPS time: 1241860094.000102519

and available on all the data streams (RAW, RAW_FULL,RDS and TREND)

Actually what we installed is a standalone UDSPT board (see attached photo). Analog i/o was connected to tiltmeter front-end electronic. Optical link was connected to mux/demux sn24, ch. 3. Board power supply was connected to Suspension Control System PDU (Port#3). Dictionary data prefix is set to ENV_NE. Tolm packet routing is set to 0xf94c000. We check proper connection of analog i/o. Connection with timing distribution was validated while DAQ connection test is pending (we are now sending 6 signals).

ITF found in Science Mode, during this period the Horizon suffered a series of drops ( see #1 plot ). It unlocked at 9:52 UTC due to a Fast unlock ( see #2 plot), I was able to reach LOW_NOISE_3_SQZ afterward but unlocked twice after a short period ( locks from 10:32 UTC to 10:37 UTC and from 10:56 UTC to 11:24 UTC ). Science Mode reached stably again at 11:45 UTC.
ITF left locked.

I have been acting on the master laser. First by resetting the noise heater (off then on again) and then by decreasing the current of the pumping diodes from 1.792 A to 1.772 A. The output power decreased from about 530 mW to 500 mW (see the attached plot). This does not impact the slave loop so much but reduces the number of possible glitches from the master laser.