(Alexa, Sheila, Kiwamu) -- a post from yesterday that didn't get uploaded due to alog maintenance

I repeated the IMC intensity noise measurement that was done for HIFOY (alog 7364):

Step 1: Measure the power spectrum of MC RIN via H1:PSL-ISS_PDA/B_CALI_DC_OUT with both the ISS off (REF 7) and on (REF 11) (see 20140318_MCRIN_Data png for these measurements).

Step 2: Calibrate via the following:

IMC_trans_freq_noise = f0/L*PWR*(2+1+1)/c/mMC2/(2*pi*f)^2 * RIN

where
f0=2.818e14 Hz    (red frequency)
L=16.4736 m       (IMC length, one way)
PWR=1.36e3 Watt   (Power in the IMC, = 8290 mWatt * Finesse/pi, Finesse=516)
mMC2=2.9kg        (Mass of MC2 mirror, same as for MC1 and MC2)
(2+1+1)           (effect of MC2 at 0deg, MC1 at 45deg, MC3 at 45deg)
f                 (Audio frequency)

This calibration is set up in matlab file: calib.m (and returns the HZ txt file). We only use PDB_DC_CALIB since this measurement gives the out of loop sensor noise (meanwhile PDA gives the in-loop). See screenshot for result.

Note: In order to ensure a proper calibration of these channels with the increased power into the MC, I adjusted H1:PSL-ISS_PDA/B_CALI_DC_GAIN such that the tsdavg was 1. PSL TEAM: does this change the gain of the loop?? Feel free to return to the nominal values. The ISS and MC still lock under the new configuration.

(all these files can be found in: /ligo/home/alexan.staley/Public/IMC_IntensityNoise/... I was not able to upload them because the files were too large)

The next step will be to insert this result into the model...TBD