Virgo Logbook

AdV-DET (Commissioning)

gouaty - 18:24 Thursday 28 July 2022 (56576)

SPRB tuning of angular setpoints

This afternoon, we adjusted the angular setpoints of the bench (TX and TY) in order to align the B4 beam on the photodiodes and the camera, while the PR CHRoCC was ON (the temperature of the CHRoCC internal heater was 350 deg).

Fig.1 shows a scan of the SPRB bench in TY while the two ITF arms were locked: The center of the plateau on the longitudinal photodiodes corresponds to TX = 122 urad.

Fig.2 shows a scan of the SPRB bench in TX while the ITF was in WI single bounce. The center of the plateau on the longitudinal photodiodes corresponds to TY = -612 urad.

An image of the B4 camera when the bench is at the position TX = 122 urad, TY = -612 urad is shown in the attached pdf.

We updated the SPRB_LC configuration with this new angular setpoints.

Previous angular setpoints of SPRB were TX = 175 and TY = -665 urad, thus both TX and TY have changed by about 50 urad.

Images attached to this report

Non-image files attached to this report

SPRB_B4_camera.pdf

Comments to this report:

gouaty - 15:40 Friday 29 July 2022 (56584)

We further adjusted the SPRB angular position this morning.

First around 7h10 utc, with CHRoCC off and cold (RH off), we recentered the B4 beam on the camera (FitPosX = -0.2, FitPosY = 0.0), new setpoints TX = 150, TY = -645
Then a few hours after switching on the CHRoCC (~12h00) we recentered the B4 camera, new setpoints TX = 143, TY = -649.5

gouaty - 15:57 Friday 29 July 2022 (56585)

New SPRB adjustment performed at 13h50 utc: TX = 139, TY = -648.

gouaty - 17:42 Monday 01 August 2022 (56599)

This afternoon I noticed that the B4 beam was misaligned on the camera B4_Cam1.

Therefore I adjusted the SPRB angular position in TY by -16 urad, in order to put the beam close to the position [FitPosX = -0.2, FitPosY = 0.0] on the camera (as we did already on friday). See attached camera image (after the recentering).

The updated angular setpoints of the bench are TX = 139 , TY = -664 urad.

Non-image files attached to this comment

SPRB_recentering.pdf

gouaty - 19:29 Tuesday 02 August 2022 (56618)

This afternoon, we observed that the B4 beam was miscentered both horizontally and vertically on the camera.

Between 17h14 and 17h21 utc we adjusted the angular setpoints of SPRB in order to recenter the beam on the camera at [FitPosX = -0.2, FitPosY = 0.0].

To this purpose, the TX setpoint had to be changed from 139 to 153 urad. And TY from -664 to -649 urad.

gouaty - 8:07 Wednesday 03 August 2022 (56623)

Performed another tuning of SPRB TY this morning to recenter B4 on the camera Cam1: position updated to TY = -654 at 06h03 utc.