[Thomas Vo, Gabriele V.]

Summary: The ITMY HWS sensor is aligned.

Still to do: check if we are on the correct beam from the IMTY HR face, by changing the ring heater and monitoring the HWS signals.

We removed the mask in front of the Hartmann sensor, and found that the beam was badly clipping on the SR3 baffle. We could fix it by moving the lower periscope picomotor.

We checked that we are imagining the right plane (i.e. the ITMY plane) by moving in angle the ITMY in pitch by about 20 urad peak to peak, and checking that the beam center of mass on the HWS moved by about 1e-3 of the image size. To do this, we modified the stream_intensity_Y.py script (located in controls@h1hwsmsr1:~/temp) to compute the center of mass of the beam intensity in X and Y and plot it as a function of the frame number (horizontal axis). In the bottom panel of the plot below you can see how the Y position of them moves when there is a 0.03 Hz pitch motion of 20 urad peak to peak.

We fine tuned the centering of the beam on the HWS by adjusting the last mirror in front of the camera. We put back the mask and got images like the one shown below.