Correy and Rahul

This morning we spent a fair bit of time damping the fundamental violin modes of the test mass - ITMY, ITMX and ETMY. Given below are the frequencies we tackled. 

1. ITMY mode 8, freq: 501.755 Hz applied gain 5 - reduction by 1 order of magnitude (amplitude)
2. ITMX, mode 2, freq: 504.891 Hz, applied gain 34
3. ETMY, mode 1, freq 510.75, applied gain 0.2

To identify the modes (between 500Hz - 520 Hz) we looked at the DTT (dignostic test tools) to obtain the real time power spectrum and a reference spectrum (from Nov 10, 2018). Next we tried looking at the SUS_CUST_VIOLIN_OVERVIEW.adl window, but we did not trust the frequencies listed over there. Hence we opened the damping filters of the test mass and looked for the closest matching frequencies. If there are two peaks very close by then we went by trial and error (apply some damping and if the amplitude decreases then we are pushing the right fibre, else set the gain back to the default value). I think with more experience we should be able to properly identify all the modes and hence update the numbers on the overview.adl window for quicker response.  

Jenne taught us a shortcut for looking at violin mode scope for a single mode, given below is the path
Locking.adl - violins scopes (pink box) -  generate single mode - feed in the test mass name and mode number to obtain the real time plot.