(Evan Hall, Borja Sorazu)

This is  a preliminary entry on the identification of 3rd violin mode harmonics with test masses (figures and further analysis will be entered later on). This information will be used to estimate mechanical losses.

Dates and times of injections: 2015-10-28 from 20:42:30 to 20:45:00 --> Injection on ITMX

                                                     2015-10-29 from 20:20:00 to 20:32:00 --> Injection on ITMY

                                                     2015-10-29 from 20:37:30 to 20:45:00 --> Injection on ETMX

                                                     2015-10-29 from 20:53:00 to 21:00:00 --> Injection on ETMY

Injection description: Fed back, in phase, DARM to penultimate mass coil drivers in pitch after bandpassing it between 1450 to 1500Hz.

Frequency modes identification (preliminary):

ITMX:

     1463.09Hz, increased by factor 4

     1467.96Hz, increased by factor 4

     1462.31Hz, decreased by factor 1.3

ITMY:

     1461.41Hz, increased by factor 4.6

     1462.03Hz, decreased by factor 4

    1463.09Hz, increased slightly

    1470.38Hz, decreased slightly

    1470. 83Hz, increased by factor 2

    1472.5Hz, decreased by factor 9

ETMX:

     1463.09Hz, decreased slightly by factor 1.077

     1471.93Hz, increased by factor 6.6

    1474.08Hz, increased by factor 4

    1475.25Hz, increased by factor 9

    1478. 17Hz, increased by factor 4

ETMY:

     1482.6Hz, increased by factor 1.75

     1484.67Hz, increased by factor of PI

Future measurement: We will do a similar injection with DARM fedback 90 degrees out of phase.