(corey, mitch) [this is work for Thursday]
Yesterday, we continued with installation/dressing of cables for SEI/ISC/SUS. Mitch completed installation of the non-SEI cables. I pinned out some Actuator cables for installation (installed one of them on H1 & still need to install the H2). I installed the GS13 Grounding Cable Bracket for Corner2.
As for Corner3....ah, Corner3.
Ideally, it would have been preferred to have installed the Cable Bracket and dressed the SEI cables before insertion of the HAM-ISI in the chamber, but we didn't have the Bracket parts, so we are installing after the fact. Corner-3 is basically entirely in the center of the Chamber. Access to it was not a problem in HAM2 (since one could climb into the chamber and work on your belly as you dressed cables & installed the bracket. But for HAM3, there is the Septum on the north of the chamber, and so this preferred space isn't useful (I tried, but I would need to shrink a factor of 4 to be useful here).
Another option was to lay on the table and then hang of the side--UPSIDE DOWN! (my Picasso-esque yoga pose [where gravitational force points down] is attached, yes that's my head at the bottom...I was resting on my left shoulder. And could only stay like this for a couple of minutes until it felt like my head was going to explode).
Since we needed to cleanly dress the GS13 cables from Stage1-to-Stage-0, I unclamped cables on the breadboard here to have a clean slate, and would like to now start dressing cables and then install the GS13 Grounding Cable Bracket (easier said than done). Will try the upsided down technique, or we will see if Jim can somehow squeeze in from the side.
Note For Future:
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Dress & install these cables/Cable Brackets BEFORE installation
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Or, hire elves
And for the record, the ballpark BOSEM calibration (+/- 50% because of variations in OSEMs open light current) is [m / ct] = (avg sensitivity * Sat Amp. Transimpendance * ADC gain)^(-1) = (62.5 [uA/mm] * 240e3 [V/A] * 2^16 / 40 [ct / V])^(-1) = 4.0e-8 [m/ct] The ballpark AOSEM calibration is about the same, [m / ct] = (avg sensitivity * Sat Amp. Transimpendance * ADC gain)^(-1) = (80 [uA/mm] * 240e3 [V/A] * 2^16 / 40 [ct / V])^(-1) = 3.2e-8 [m/ct]What was done:
Disabled VCO to ETMY offloading servo.
Disabled L1 damping.
Injected 0.1Hz 30000 counts excitation into ETMY M0 L lock filter (though I should have done this to DAMP L filters in a retrospect to make it simpler).
Measured the transfer coefficient from the exc to Lock filter output and OSEM DAMP L input of M0, L1, L2, and H2:ISC-ALS_EY_ARM_IN1_DQ which is calibrated in nm for the entire frequency range.
H2:ISC-ALS_EY_ARM_IN1_DQ had a coherence of 0.995 for an average of 5, everything else had a coherence of practically 1.
Since M0 damping might have some effect on the measurement (and that's the reason why I should have injected into DAMP_L), I "reproduced" the overall length drive output by adding TEST filter output and DAMP_L filter output transfer coefficients. In the end that didn't matter (only made 1% change).
Drive calibration = [H2:ISC-ALS_EY_ARM_IN1_DQ]/[reconstructed length drive].
Sensing calibration = [H2:ISC-ALS_EY_ARM_IN1_DQ]/[DAMP_L_IN1_DQ].
Measuement files are here:
/ligo/home/controls/keita.kawabe/OAT_2012/EY_cal