This is the calculation I didn't write yesterday because I was sleepy.
As reported, we monitored the change in pitch produced by the Trupm procedure with the oplev, but we can also use the OSEMs.
- The values of the OSEMs before and after the Trupm procedure were
- V2: 41 µm → 228 µm.
- V3: -19 µm → 188 µm.
- Because these OSEMs are sensitive to roll also, to calculate the change in their readouts related to pitch, we must consider the average before and after:
- Before: 11 µm.
- After: 208 µm.
- Difference: S = 197 µm.
- The distance from the OSEMs V2 and V3 to the suspension rod (see details in this diagram) is R = 48 mm.
- Then, the change in pitch ( S / R ) = 4.1 mrad. This number is consistent with what we measured when we glued the wire and disturbed the alignment (3.8 mrad, see this notebook page ) and also with the measurement carried yesterday morning from the control room (-3.9 mrad).