Aidan. Alastair

Following a successful install of the HWSY correction, we realigned the HWSX optical system to accomodate a change in the green leakage field from four weeks ago (probably due to changes in alignment of the BS and SR3). We coarsely matched the ALS and 800nm optical axes through the irises. We fine-tuned the centering of the probe beam to the ITM by observing the location of the center of the intensity relative to the center of the shadow from the BS and tweaking the alignment of the upper periscope mirror to get the intensity distribution concentric with the shadow.

We will run RH tests in the morning to try to ascertain the exact location of the centers of the ITMs in the HWS coordinates.

However: when I turned on the HWS-Y SLED, the HWS-X sensor started going haywire. By reviewing the camera stream from HWS-X itself, it became clear that some of the HWS-Y probe beam is making it into the HWS-X camera. We haven't yet figured out what this leakage path is. We can still run the sensors one at a time as diagnostics. Only HWS-X is currently running.

And: we're seeing glitches in the frames from HWS-X that have been seen before. They manifest as part of the image being transpose with another part of the image. This is clearly a digital issue (probably access of the framegrabber). It has really only been observed when we try to access both cameras from the framegrabber.

Images of the HWS-X camera stream, with and without the HWS-Y probe beam turned on, are attached.