travis.sadecki@LIGO.ORG - posted 17:23, Wednesday 02 May 2018 - last comment - 02:38, Friday 04 May 2018(41813)
ETMx re-welding day 3
All fibers welded and annealed. After a couple of iterations of pitch correction annealing, we wound up with a final differential pitch of ~190 µrad. More stats and photos to follow soon.
Comments related to this report
jason.oberling@LIGO.ORG - 17:50, Thursday 03 May 2018 (41833)
Final alignment numbers for the ETMx fiber weld, round 2. All measurements were done with the ETMx suspended; the PUM and UIM were both locked. All numbers assume the reader is looking in the -X direction (i.e. at the AR surface of the ETMx); this is opposite the notation used in the alignment notebook, which is done from the perspective of the alignment equipment (i.e. looking at the HR surface of the ETMx). All measurements were done after yesterday's correction of the differential pitch; before the correction the differential pitch was 2.94 mrad down.
Roll
PUM: <0.1 mm CW
ETMx: 0.25 mm CW
Pitch
PUM: 1.1 mrad up
ETMx: 1.29 mrad up
Differential: 190 µrad up
Fiber Stretch
Left: 5.9 mm
Right: 6.3 mm
PUM/ETMx Center of Mass Separation
Left: 601.3 mm
Right: 601.7 mm
The serial numbers of the fibers used and their location in the monolithic are as follows:
+X/+Y
S1800648
+X/-Y
S1800654
-X/+Y
S1800665
-X/-Y
S1800494
The serial numbers of fibers rendered unusable during the welding process are:
S1800464
S1800492
borja.sorazu@LIGO.ORG - 02:38, Friday 04 May 2018 (41837)DetChar
After reading Jason's comment I would like to stress that it is very important for future characterization of the suspensions and violin modes, to use the official identification conventions for the fibres. Recently, I wrote a DCC document that summarizes the two conventions we ever used (global coordinates convention and local mass face-on convention) and shows the fibre identification in these 2 conventions for all test masses. Please use this document as a reference.
Final alignment numbers for the ETMx fiber weld, round 2. All measurements were done with the ETMx suspended; the PUM and UIM were both locked. All numbers assume the reader is looking in the -X direction (i.e. at the AR surface of the ETMx); this is opposite the notation used in the alignment notebook, which is done from the perspective of the alignment equipment (i.e. looking at the HR surface of the ETMx). All measurements were done after yesterday's correction of the differential pitch; before the correction the differential pitch was 2.94 mrad down.
The serial numbers of the fibers used and their location in the monolithic are as follows:
The serial numbers of fibers rendered unusable during the welding process are:
After reading Jason's comment I would like to stress that it is very important for future characterization of the suspensions and violin modes, to use the official identification conventions for the fibres. Recently, I wrote a DCC document that summarizes the two conventions we ever used (global coordinates convention and local mass face-on convention) and shows the fibre identification in these 2 conventions for all test masses. Please use this document as a reference.