Yesterday I worked a bit on the optimization of the ID for ETMX

In the First version of ID implemented at ETMX, using geophones, I set the blending frequency for L and T at 180 mHz: in this configuration the loops were stable, but seismic noise was not suppressed.
So I tried to implement a new version of ID moving the blending frequency from 180 mHz (in L and T) to 150 mHz.
Before I worked a bit on the optimization of the geophone signal:

1) I checked the calobration factor
2) I checked the sensing matrix of the geophones (following the procedure describe in the see klog 8327)
4) I implemented the the new blending frequency (LP155, HP150 Pic1).
5) I turned on the ID only along L and T with UGF (first cross)  at 0.12 mHz.
6) Y is controlled with LVDT. 

The loops are stable.

In Pic 2, Pic2 and Pic4 the SPectra of IP , BF (L,T,Y) and TM (P,Y,L) and the relative rms, when the following configuration on the IP are implemented, are shown:

-Blu: IP in position control

-Magenta: IP Position control+ IP sensor correction

- Red : IP ID on

-Black: ID+ sensor correction on

We can see that:

1) IP RMS  in the configuration ID+ sensor correction  is 0.03 micron in L and T

2) In both cases (ID and ID + sens correction on) the  BF RMS  is 0.1 micron in L and T and 0.09 microradiands, but the peack at 0.08 Hz and 0.150 Hz is growing up (investigation on going).

3) From 0.1 to 0.3 TM P, Y motion is reduced because of the ID.

Note:

1)In both configuaration BF_L , BF_T damping loops  were also turned on.

2) This version of ID is running from yestarday afternoon.