Reports until 15:58, Monday 23 October 2017
H1 SUS (DetChar)
jeffrey.kissel@LIGO.ORG - posted 15:58, Monday 23 October 2017 - last comment - 13:51, Wednesday 25 October 2017(39135)
Newly Suspended ITMX Fiber Violin Modes Characterized 
J. Kissel, T. Sadecki

Travis and I spend the day characterizing the violin modes of the new fibers on the new ITMX main chain, after confirming it was "mostly free" last week (see LHO aLOG 39111) with the same HeNe laser + QPD setup as described in LHO aLOG 38857. Processed data to come, but I'm building up quite the backlog... stay tuned, and thanks for your patience.
Comments related to this report
jeffrey.kissel@LIGO.ORG - 13:51, Wednesday 25 October 2017 (39163)
Link 

Processed data from the fully suspended measurements mentioned above are attached.

Partially suspended data is from LHO aLOG 38965.

Here're the results in tabular form, comparing partially suspended and fully suspended data, and their difference:

Fiber       S/N         Harmonic     Partially      Fully       df (F-P)
+X / +Y     S1400158    Fund.        502.45        502.422       -0.0281
                        2nd          994.8         994.188       -0.613
                        3rd         1463.8        1463.719       -0.0810
                        4th        (1930.0)       1930.0          0.0
                        5th        [2390.0]       2388.75        -1.25
                        6th          No Data      2819.13         n/a

-X / +Y     S1400137    Fund.        503.96       503.891        -0.0694
                        2nd          997.85       997.484        -0.366
                        3rd         1468.3       1467.72         -0.581
                        4th         1931.6       1930.98         -0.616
                        5th        (2391.0)      2390.50         -0.500
                        6th          No Data     2858.44          n/a

+X / -Y     S1400154    Fund.        504.45       504.250        -0.200
                        2nd         1002.6       1002.36         -0.241
                        3rd         1466.6       1466.16         -0.444
                        4th         1936.4       1935.83         -0.572
                        5th         2390.0       2400.00         10.0
                        6th         No Data      2856             n/a
 
-X / -Y     S1400164    Fund.        504.71      504.594         -0.116
                        2nd         1001.6      1001.25          -0.350
                        3rd         1472.4      1472.11          -0.291
                        4th         1940.3      1939.91          -0.394
                        5th         2408.3      2407.31          -0.987
                        6th          No Data     No Data          n/a


The resolution/uncertainty of the first four harmonics of fully suspended data is +/- 15.6 mHz, and that of the 5th and 6th is 62.5 mHz. However, the data in both partially and fully suspended cases show the Qs are particularly low so the above numbers have a grain of salt.

With all of the above caveats, one can see there is a systematic shift in frequency downward from partially- to fully-suspended, with a mean and std of (F-P) = -0.31 +/- 0.22 Hz (ignoring the poor-data quality of the 5th harmonic). My impression from the Glasgow team is that this is expected, given the changes in boundary conditions that arise from suspending the PUM.
Non-image files attached to this comment