sheila.dwyer@LIGO.ORG - posted 07:34, Tuesday 29 September 2015 - last comment - 22:41, Tuesday 29 September 2015(22050)
running A2L script
Since LLO had already gone down (we think for maintence) TJ let me start some maintence work that needs the full IFO locked. at about 14:32 UTC Sept 29th we went to commisioning to start running the A2L script as described in WP # 5517.
The script finished right before an EQ knocked us out of lock. Attached are results, we can decide if we are keeping these decouplings durring the maintence window.
The three changes made by the script which I would like to keep are ETMX pit, ETMY yaw, and ITMY pit. These three gains are accepted in SDF. Since we aren't going to do the other work described in the WP, this is now finished.
All the results from the script are:
ETMX pit changed from 1.263 to 1.069 (1st attachment, keep)
ETMX yaw reverted (script changed it from 0.749 to 1.1723 based on the fit shown in the second attachment)
ETMY pit reverted (script changed it from 0.26 to 0.14 based on the 3rd attachement)
ETMY yaw changed from -0.42 to -0.509, based on fit shown in 4th attachment
ITMX no changes were made by the script, 5th +6th attchments
ITMY pit (from 1.37 to 1.13 based on 7th attachment, keep)
ITMY yaw reverted (changed from -2.174 to -1.7, based on the 8th attachment which does not seem like a good fit)
By the way, the script that I ran to find the decoupling gains is in userapps/isc/common/decoup/run_a2l_vII.sh Perhaps next time we use this we should try a higher drive amplitude, to try to get better fits.
I ran Hang's script that uses the A2L gains to determine a spot position (alog 19904), here are the values after running the script today.
I also re-ran this script for the old gains,
vertical(mm)
So the changes amount to +0.4 mm in the horizontal direction on ETMY, -0.9 mm in the vertical direction on ETMX, and -1.1mm in the vertical direction on ITMY.
Please be aware that in my code estimating beam's position, I neglected the L2 angle -> L3 length coupling, which would induce
an error of l_ex / theta_L3,
where l_ex is the length induced by L2a->L3l coupling when we dither L2, and theta_L3 is the angle L3 tilts through L2a->L3a.
Sorry about that...