Virgo Logbook

I made a (boring ) list of spectral peaks of today (22MpC) with the last good lock of 35MpC done June 25, before increasing the power.

The present sensitivity allows a first insight of the peaks after the SDB1 scattering light mitigation

A few general commments:

several peaks have disappeared (especially between 100 and 400Hz) while few remained or appeared mainly between 400 and 500Hz (Figure 1)
sidebands of 100Hz associated to timing have much reduced
large 150Hz and 350Hz, about 10 times more intense
there are large sidebands (about 0.75Hz and 1.5Hz apart) around several mains harmonics, the most evident are around 150Hz, these were not present before
there is some coherence with DT accelerometer, especially at some peaks around 400Hz and 450Hz
we use bruco coherence tables from this link: https://scientists.virgo-gw.eu/DataAnalysis/bruco//2018-08-23/
Figur e 1: all frequencies
Figure 2 : 50Hz
Figure 3: 100-200Hz
Figure 4: 200-400Hz
Figure 5: 400-500Hz
Figure 6: peak 343
Figure 7: peak 391
Figure 8: peak 458

It follows a list with details:

(note that the LNFS was left free running, so there is no 1Hz comb noise. Also note that Hrec still needs a calibration. Compare with the list of peaks described for June 25: 42006)

Freq(Hz) notes
15.8 CALnoise WE_MAR_permline0 15.8
16.8 CALnoise_NE_MAR_permline1 16.8

(20 Hz peak is only in DARM, it gets subtracted in hrec, as all noise coherent with B2_8MHz)
23.8 new
35.0 PCAL NEB
36.5 PCAL WEB
50 Hz and bump, looks the same (little peaks on the left of it 48.3, 47.8 are more or less same)
60.5 PCAL WEB
61.0 CALnoise BS_MIR_permline1 61.0
61.5 CALnoise WE_MIR_permline1 61.5
62.5 CALnoise NE_MIR_permline1 62.5
63 .0 CALnoise PR_MIR_permline1 63.0
63.5 PCAL NEB
71.4 new
87.1 SDB1_OMC line_DARM 87.1
(100Hz sidebands much reduced... thanks to timing upgrade)
101.0 Hz (frequency noise, still there) coherence with SSFS, INJ_z, ENV_IB_ACC and some SBE_EIB_geo* (see previous investigations 1 and 2)
(106Hz (power supply of INJ mini rack) disappeared)
(107Hz (picomotors of INJ mini rack) removed)
(111Hz removed)
119Hz is new (little coherence with WEB and NEB clocks)
139.8 is new (coherence with SSFS, INJ_z)
150 Hz is significantly LARGER and has with two big horns at +-1.5Hz (145 to 158 there is coherence with INJ signals, suspect is electrical noise, ...)
157.3 Hz (frequency noise, possibile SDB1 mode) still there, coherence with INJ_z
159.4 Hz (likely the 3rd harmonics of small INJ rack power supply now at 53.14Hz) also seen in SBE_EIB_geobench1
200 Hz: surrounding structure changed (seems no more symmetric sidebands)
(disappeared peak 192.5Hz, known SDB1 mount)
(disappeared 219Hz line, related to timing)
250 and sidebands spaced by 0.7Hz or 0.8Hz
(several peaks disappeared btw 220 and 300Hz)
276.8 (remained) (coherent with PRCL, B2_8MHz)

279 (remained) (coherent with PRCL, B2_8MHz)

290 Hz, new, some coherence with DT Accelerometer, SIB2_B2 quadrants, ACS_B2 quadrants
300 Hz still has large sidebands that now moved to about +-0.7Hz and =- 1.5Hz (resemble the ones of 150Hz, 250Hz)
(disappeared 333.3Hz)
343.7 new (coherent with DT accelerometers) (Figure 6)

345.3 Hz new (coherent with SPRB_LINK accelerometer)
350 Hz and sidebands around 350Hz, =-1.5Hz
355.5 CALnoise WE_PCAL_permline2 355.5
356.0 CALnoise BS_MIR_permline2 356.0 it is coherent wih Accelerometer EDB...why?
356.5 CALnoise WE_MIR_permline2 356.5
357.5 CALnoise NE_MIR_permline2 357.5
358.0 CALnoise PR_MIR_permline2 358.0, it is coherent wih Accelerometer EDB...why?
359.0 CALnoise NE_PCAL_permline2 359.0, it is coherent wih Accelerometer EDB...why?

new peaks at 390.3,391.7 and 393.4 (1.5Hz spacing) the central peak 392 is coherent with acc DT tower and oter in CEB (Turbo pump?) Figure 7

401.3 (turbo pump) is broader in hrec (why?) and seems to have sidebands ....
412.4 (small) coherent with DT accelerometer
418.9 (still there, now bigger) ...coherent with DT acc
(peaks 428 and 433 removed)
new "COMB": 455.5, 456.5, 458, 460, 461.1, 463, 464.1 (463 has clear coherence with DT accelerometer, suspect big turbo) Figure 8

some larger broad noise btw 480 and 500
480 Hz, some coherence with DT ACC
500 Hz has now sidebands at +-1.5Hz