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Virgo Runs (O4b)
Sposito - 15:01 Tuesday 30 April 2024 (64135) Print this report
Operator Report - Morning shift

ITF is found in SCIENCE. 

At 6:01 UTC I set the ITF in Maintenance Mode, here is the list of the activities communicated to the Control Room:

Periodic Tasks carried out by the Operator:

  • From 6:19 UTC to 6:36 UTC, Check of IMC Working Point and Position;
  • 07:04-07:09 UTC OMC locked in SINGLE_BOUNCE_NI
  • From 7:11 UTC to 7:32 UTC - OMC Scan in Single Bounce configuration;
  • At 8:00 UTC - TCS Thermal Camera Reference;
  • At around 06:23 - 06:35 UTC - TCS Power Checks (see table below for results):
  CH (W) Inner DAS (W)  Outer DAS (W)
W Pickoff 0.255 0 0.22
N Pickoff 0.68 0.065 0.602

11:25 UTC Maintenance ended, I re-aligned the CITF and relocked the ITF at the first attempt, back in SCIENCE at 11:35 UTC.

11:58 UTC Vpm restarted

SQZ not working properly, F. Sorrentino contacted H. Valbruch for it.

Sub-system reports

I changed the set-points of NI and WI etalon suggested by M. Mantovani.
12:13 UTC WI new set point 19.825 and NI new set point 20.1

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Comments to this report:
cabrita - 11:02 Monday 06 May 2024 (64178) Print this report

In a similar way to how the PRC gain is computed using the phase camera, I computed the dark port transfer function of the carrier using the B1p phase camera data.

I used 10 mins of the single bounce data during the OMC calibration as Pref and looked at 10mins of data after 1 hour of science mode (Pscience). The dark port transfer function for the carrier is then: TF = Pscience/Pref*Tprm*Tbs*Rinput*Tbs*Tsrm

Using the values from the OptChar page:

Tprm = 0.04835; Tsrm = 0.396; Tbs = 0.5; Rinput = 1-0.01377;

The dark port transfer function is shown after 1 hour of science run is shown in figure 1.

Using the input power (17 W), we can estimate the carrier power in the dark port, shown in figure 2. On average, after 1 hour of science mode the carrier power at the dark port was 0.0884 W, versus 0.1034 at the start of science mode.

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cabrita, mwas - 10:55 Wednesday 08 May 2024 (64209) Print this report

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.

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