IMMT1 trans QPD Pitch. In the attached figure,

• Green: on Mar. 6 around 9:00 JST before start working of 24247. IFI-IMM-PRM chambers were in air. The copper wire was still there.
• Blue: on Mar. 6 after the work. Air was still within those chambers. The copper wire was detached.
• Red: After switching to the ion pump; see 24288. The noise floor increased due to input power reduction (around 3 W for Green and blue, but 1.1W for red)

Most of the peaks disappeared, but

• Some new structures seemingly appear. Why...??? Occasionally??
• The peak at 127 Hz is still there. It is surviving. For example, tapping the IFI chamber makes this peak much grow up, so the critical path would not be cut yet... but what is that?