daniel.sigg@LIGO.ORG - posted 23:13, Friday 14 February 2014 - last comment - 08:25, Tuesday 18 February 2014(10118)
ALS WFS in EX
(Blue Team)
Short progress report:
- All necessary electronics modules and chassis have been installed in EX.
- All cables were installed.
- Beam profiles were measured and the sensor heads are installed on ISCTEX.
- The isc model has been updated to include code for the ALS WFS.
- The asc model has been updated to receive the angular feedback signals and to provide the green transmitted light.
- Slow inputs into the alignment servos are available to support camera spot position of ITM and ETM.
- Feedback paths are available to control the ITM and ETM mirror orientations but not TMS.
- The ALS end station medm screen has been updated to include the ALS WFS.
- The slow controls system in EX has been updated to support the new whitening chassis.
- There are currently no readbacks for the demodulator RF monitors.
More details to follow.
Comments related to this report
- "50:50 splitter" turns out to be more like 20:80. Due to this, WFSA interface was set to high DC gain mode while WFSB is low.
- Things were put in place based on Jax's calculation, without measuring the beam. Beam profile was measured at some places but it was so ugly I don't think it makes much sense to make an analysis.
- The first attachment is the beam profile right after the beam is picked off of the REFL diode path. Ugly.
- The second is the profile of the beam going into the chamber upstream of the 1" lens (between L6 and M9). One side is clipped off. I don't post all pictures but the beam is reasonable after the first Faraday, not terrible after EO, bad after the second Faraday.
- A part of the problem seems to be in the input beam. Didn't try to "fix" it, as the past attempts to do so with existing components failed multiple times in OAT. I really believe that we need to put Faraday on an adjustable mount.
- DC path is working, so are the picos.
- RF path is yet to be checked.
Images attached to this comment
