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AdV-INJ (Beam Pointing Control)
derossi, mantovani - 19:59 Thursday 20 February 2025 (66227) Print this report
BPC noise injections

The goal of the shift is to measure the beam jitter coupling to the sensitivity in LN2 and LN3, because the measurement we have are too old. This will be useful to give an upper limit for phase II.

DSP card damping-adv BPCCD
page 4 wnoise 1
bpnoise bpnoise.flt 0.01 ( 2 zeros with Q=0 @0Hz, 1 pole with Q=0.5 @30Hz antd 1 pole with Q=0.5 @300Hz)
bp noise noise 1

amplitude set ont the dofs txcorr, tycorr, xcorr, ycorr

 

%%%  LN3  %%%

  gps start duration amplitude ITF status
clean 16:28:00 UTC     LN3
TX 1424104578 (16:36:00 UTC) 2 min 0.5 x 0.01 LN3
TY 1424195015 (16:43:20 UTC) 4 min 1.5 x 0.01 LN3 (attached fig. as example)
TX 1424105396 (16:49:40 UTC) 4 min 0.5 x 0.01 LN3
X 1424105940 (16:58:40 UTC) 4 min 10 x 0.01 LN3
Y 1424106374 (17:06:00 UTC) 4 min 10 x 0.01 LN3

 

%%%  LN2 %%%

  gps start duration amplitude ITF status
clean 18:19:00 UTC 2 min   LN2
TX 1424110999 (18:23:00 UTC) 4 min 0.5 x 0.01 LN2
TY 1424111568 (18:33:00 UTC) 4 min 1 x 0.01 LN2
X 1424112122 (18:41:30 UTC) 4 min 10 x 0.01 LN2
Y 1424112500 (18:48:30 UTC) 4 min 10 x 0.01 LN2
TY 1424112839 (18:54:00 UTC) 4 min 1.5 x 0.01 LN2
clean 19:00:00 UTC 4 min   LN2
Images attached to this report
Comments to this report:
derossi, mantovani - 11:35 Monday 24 February 2025 (66241) Print this report

From an analysis of the noise injections we observed that:

- the transfer functions of X, Y, TX and TY are slightly different from LN2 to LN3 (fig. 1 to 4)

- in LN2 the jitter coupling is closer to limit the sensitivy than in LN3

- the CMRF in LN3 is a factor 2 lower than in LN2 (fig. 7 and 8 the amplitude of the 1111Hz line). This is due to the fact that the BS TY servo is engaged only in LN3.

Images attached to this comment
mwas - 11:57 Thursday 06 March 2025 (66244) Print this report

This comment from a few weeks ago went back into draft, posting it again.

To study couplings at ~100Hz it is better to look at the frequency line at 227.1Hz instead of the 1111Hz line to judge changes in the CMRF. The CMRF is frequency dependent, so the line at 227.1Hz line will be more representative of the coupling around 100Hz.

mantovani - 16:22 Monday 10 March 2025 (66336) Print this report

We had checked also the line @ 227.1Hz and the ratio of the line was the same wrt the 1111Hz

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