J. Kissel, S. Karki, B. Weaver, R. McCarthy, G. Merano, M. Landry
After gathering the weekly charge measurements, I've compared H1 SUS ETMY ESD's relative Pitch/Yaw actuation strength change (as measued by the optical levers) against the Longitundinal Actuation Strength (as measured by PCAL / ESD calibration lines). As has been shown previously (see LHO aLOG 22903), the pitch/yaw strength's slope trends very nicely along with the longituinal stength change -- if you take a quick glance. Upon closer investigation, here are things that one begins to question:
(1) We still don't understand why the optical level actuation strength assessments are offset from the longitunidal strength assessment after the ESD bias sign flip.
(2) One *could* argue that, although prior to the flip the eye-ball-average of oplev measurements trackes the longitudinal strength, after the flip there are periods where two quadrants (magenta, in pitch, which is LR, from Oct 25 to Nov 8; black, in yaw, which is UR, from ~Nov 11 to Dec 06) track the longitudinal strength. As such, one *could* argue that the longitudinal actuation strength trend is dominated by a single quadrant's charge, instead of the average. Maybe.
(3) If you squint, you *could* say that the longitudinal actuation strength increase rate is slowly tapering off, where as the optical lever strength increase *may* be remaining constant. One could probably also say that the rate of strength increase is different between oplevs and cal lines (oplev P/Y strength is increasing faster that cal line L strength).
All this being said, we are still unsure whether we want to flip the ETMY ESD bias sign again before the observation run is out. Landry suggests we either do it mid-December (say the week of Dec 14), or not at all. So we'll continue to track via optical lever, and compare against the longitudinal estimate from cal lines.
Results continue to look encouraging for ETMX -- ever since we've had great duty cycle, and turned off the ETMX ESD Bias when we're in low-noise and/or when the IFO is down, the charging rate has decreased. Even though the actuation strength of ETMX doesn't matter at the few % level like it does for ETMY (because ETMX is not used as the DARM actuator in nominal low-noise, so it doesn't affect the IFO calibration), it's still good to know that we can get an appreciable effect by simply reducing the bias voltage and/or turning it off for estended periods of time. This again argues for going the LLO route of decreasing the ETMY bias by a factor of 2, which we should certianly consider doing after O1.
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As usual, I've followed the instructions from the aWiki to take the measurements. I had much less trouble today than I had last week gathering data from NDS, which is encouraging. One thing I'd done differently was wait a litle longer before requesting the gathering and analysis (I waited until the *next* measurement had gone through -9.0 and -4.0 [V] bias voltage points and started the 0.0 [V] point, roughly 5 minutes after the measurement I wanted to analyze ended). As such, I was able to get 6 and 4 oplev data point to compose the average for ETMX and ETMY, respectively (as opposed to the 3 and 1 I got last week; see LHO aLOG 23717).
Once all data was analyzed, I created the usual optical-lever-only assessment using
/ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/Scripts/Long_Trend.m
and saved the data to here:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O1/H1/Results/CAL_PARAM/2015-12-01_H1SUSETMY_ChargeMeasResults.mat
However, I'd asked Sudarshan to gather the latest calibration line estimates of the ESD longitudinal actuation strength (aka kappa_TST), which he gathered from his matlab tool that gathers the output of the GDS function "Standard Line Monitor." (He's promised me an updated procedure and an aLOG so that anyone can do it). This is noteably *not* the output of the GDS pipeline, but the answers should be equivalent. His data lives here:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O1/H1/Results/CAL_PARAM/2015-12-01_Sep-Oct-Nov_ALLKappas.mat
Finally, I've made the comparison between oplev and cal live strength estimates using
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O1/H1/Scripts/CAL_PARAM/compare_chargevskappaTST_20151201.m
