Yesterday I went to end X to investigate the beam shape for the ALS WFS.  (This is to follow up the measurements we made in alog 10774)

First I tried changing the alingment of the reaction chain, this didn't make a difference.  Then I tried changing the TMS QPD offsets.  This moves the lock point of the input alingment loops, changing the alingment of the green beam as it goes through TMS.  This certaintly changes the beam quality on the WFS, screenshots of several different offsets are attached.  In the end I left the offsets at ALS-X_IP_ANG_PIT at -50, ALS-X_IP_POS_PIT at 150. 

I am not sure why changing these offsets makes such a difference in the beam quality. 

This moved the QPD A by 0.07 counts and QPD B by 0.04 counts.  Pablo and I redid the pointing of TMS to the baffle PDs, but it hadn't changed more than the normal change between ISI trips.  However, switching these offsets does move the beamspot on ISCT1, I moved PR3 by 0.9urad in pitch to bring the spot back.  

After realinging the arm, we re checked the phasing of the WFS. We did this by putting an exictation on LSC-X_EXTRA_AO_1_EXC at 50Hz and looking at the signals of the individual segments, which seems fine.  This is saved in /home/sheila.dwyer/ALS?HIFOX/WFS/WFS_PhaseDTT_March282014.xml

Then we started the sensing matrix measurement in Alexa's alog 11073