Transfer functions of the ITMX at the test-stand have been running overnight yesterday, after last alignement. The attached plots are showing :

(1) M0-M0 undamped transfer functions for the 6 dofs, compared against  "wire rehang" model

(2) R0-R0 undamped transfer functions for the 6 dofs, compared against "thincp" model

Main chain was showing source of rubbing (all dofs of first attachement, except yaw). It turned out that during those measurements, an EQ stop was touching the top of the M0 test mass (main chain). It has been pulled back this morning. Reaction chain looks similar to the model, except for pitch, which we assume

(3) Spectra of ITMX in euler basis for main and reaction chain :

-after alignement of main chain, reaction chain not aligned (blue curve Sept 04th )

-after alignement of main and reaction chain, EQ stop touching the test mass (green curve Sept 10th)

-after alignement of main and reaction chain, after pulling back the EQ stop (red curve Sept 10th)

Looking at the vertical dof of main chain for eg, page 9, we can see that the frequency of the first mode of vertical (0.55Hz) reappeared after the EQ has been moved. 

Data, script and result files will be commited on the svn after this entry.

Transfer functions for ITMX will be running again overnight