Abstract:
I performed a cable swapping test for investigating the problem.
As a result, the problem doesn't seem to be inside the vacuum chamber, and we can probably proceed the evacuation without solving this problem.
Detail:
I did the cable swapping test for investigating if the source of the glitches is inside the vacuum chamber or not.
I disconnected the F2 and F3 LVDT cables at the feedthrough port and swap them.
Swapping work was started from 10:43 JST and finished at 10:51 JST.
Figure 1 shows the LVDT signals when F2 and F3 cables were swapped.
As you can see, glitches are still on the F3 signals even though the cables were swapped.
This implies that the origin of the glitches are outside of the vacuum chamber.
I also checked the spectra before and after swapping the cables (fig2, red: after swapping, blue: before swapping).
As you can see, F3 signals became better when cables were swapped while F2 signals became worse.
Note that F2 and F3 signals after swapping (red) can be seen at F3 and F2 channels, respectively, because of the swapping.
So, the electrical circuits are doubtful.
Note:
Measured spectra were stored at /users/VISsvn/TypeAtower/ITMX/Measurements/20211220/SPE_ITMX_GAS_swappingtest_20211220.xml.
