Reports until 19:47, Monday 09 March 2015
H1 ISC
stefan.ballmer@LIGO.ORG - posted 19:47, Monday 09 March 2015 - last comment - 19:13, Wednesday 11 March 2015(17151)
New DARM filters implemented 
Alexa, Sheila, Evan, Chris, Stefan

We implemented Peter's DARM 'SUScomp' from alog  16728. Since we can't lock with that filter directly (see alog 16840), deleted the old 'LLO' filter, but instead loaded a difference filter called 'acqLP' that makes the 'SUScomp' look like the old 'LLO' filter:
  zpk([80;500-800i;500+800i],[50;70;200],1,"n")

Guardian was updated to turn off acqLP' in FM8 instead of turning on a lead.



A note on the previous filter is also found in alog 16381.
Comments related to this report
alexan.staley@LIGO.ORG - 20:04, Monday 09 March 2015 (17152)
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I have attached a plot comparing our various configurations:

1. Red trace: RF DARM sus compenstation as designed by Peter to obtain more phase margin. The LSC DARM configuration is: FM1(suscomp), FM2(2:0), FM3(resG), FM4(4^2:1^2), FM5(2:0), Gain 800 (LHO#16728, 16840)

2. Blue trace: Our old RF DARM sus compenstation where we used the LLO control filer and a 200Hz lead filter. (LHO#16381)

3. Green trace: ALS DIFF sus compensation. This is the configuration we use to lock ALS DIFF. The LSC DARM configuration is: FM1(suscomp), FM2(2:0), FM3(resG), FM7(SB60), FM8(acqLP),FM10(RLP33), Gain 400. As Stefan mentioned, FM1+FM8 returns our old LLO control filter.

 

I have also attached the RF DARM OLTF model with the new (red) and old (blue) configuration as described above, along with the respective measured data. The RF DARM UGF is now 55 Hz with a phase margin of ~45deg.

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evan.hall@LIGO.ORG - 20:00, Monday 09 March 2015 (17153)
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Measurement of new DARM loop on dc readout is attached.

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jeffrey.kissel@LIGO.ORG - 07:58, Tuesday 10 March 2015 (17160)CAL
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I've saved Evan's .xml to the calibration repository here:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Measurements/DARMOLGTFs/2015-03-09_DARM_OLGTF_LHOaLOG17153.xml
and exported text files of the transfer function and coherence,
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Measurements/DARMOLGTFs/
2015-03-09_H1_DARM_OLGTF_LHOaLOG17153_coh.txt
2015-03-09_H1_DARM_OLGTF_LHOaLOG17153_tf.txt

Transfer function contains the following columns (i.e. I exported IN1 / IN2 "as is"):
Frequency [Hz]    Real Part [ ]    Imaginary Part [ ]

We'll use later for calibration / noisebudget model verification!
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evan.hall@LIGO.ORG - 10:32, Wednesday 11 March 2015 (17196)
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Also including the CARM OLTF that we took at 9 W.

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kiwamu.izumi@LIGO.ORG - 19:13, Wednesday 11 March 2015 (17206)ISC
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I checked the measured DARM open loop transfer function posted by Evan against my DARM open loop model. Even though I did not do a fitting or any fancy analysis yet, it seems that the optical gain was consistent -- the measurement matched the model with an optical gain of 1.1x106 cnts/m or 9.09x10-7 m/cnts which we have been using since Feb. 21st (alog 16843) for the CAL-CS front end model.

Here is a plot showing the model and measured one:

The matlab script to generate this plot is archived in calSVN:

 /ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Scripts/DARM_OLTFGTF_LHOaLOG17153.m

 

Note for myself:

optical gain in the model = 1.1e6

ESD strength in the model = 2.8e-10 [N/V^2] (see alog 16843)

LSC_DARM_GAIN = 800 (instead of 400)

Only ETMX was actuated

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