We performed several actions. The list of gps and details are il the attached log file.
switch off of 600N and 600W vacuum pump stations and UPS
we observed a reduction of magnetic noise in CEB, mailing at ~13 Hz sidebads of the 50 Hz and harmonics. Figures 1 and 2.
global site-wide HVAC switch off:
- NEB and WEB; switched of AHU, cold water pump and chiller
- CEB: AHU of clean rooms, hall, det lab, inj lab
Figure 3 shows the temperature change and the BNS range. The BNS range progressively improved by ~2Mpc during the switch off (which started at ~16:00 UTC). Yet, this improvement might instead be due to the ongoing thermal transient (TCS RH tuning). The ITF unlocked (IMC unlock) before we could observe the effect of the reverse switch on actions.
disconnection of the cables of the NI and WI ring heaters
Both power supplies were on but set to zero. We disconnected the cables. Once relocked we observed a very large broadband noise in Hrec below ~100 Hz, with a very large 50 Hz. Therefore we connected to ground (tower vac chamber body) all the cables. The broadband noise disappeared, the 50 Hz reduced, but some excess remained. The glitches did not disappeared. We reconnected all cables.
Change the CEB hall temperature
We forced a fast decrease in temperature of the CEB hall by closing the hot water flux and opening to max the cold water flux of the hall HVAC. The temperature reduced by 2 degrees in 40minutes. It seems that the rate of the glitches did not change significantly. To be better analyzed. Figure 4.
