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Entry  Fri Dec 12 22:51:23 2008, Yoichi, Update, PSL, Reference cavity ring down measurement again RC-Ringdown.png
    Reply  Tue Dec 16 19:06:01 2008, Yoichi, Update, PSL, Reference cavity ring down repeated many times RC_Ringdown_Estimates.pngCavity_Pole_Histogram.png
Message ID: 1191     Entry time: Tue Dec 16 19:06:01 2008     In reply to: 1190
Author: Yoichi 
Type: Update 
Category: PSL 
Subject: Reference cavity ring down repeated many times 
Today, I repeated the reference cavity ring down measurement many times to see how much the results vary.

I repeated the ring down for 20 times and the first attachment shows the comparison of the measured and estimated cavity transmission power.
The blue curve is the measured one, and the red curve is the estimated one. There are only 10 plots because I made a mistake when transferring data
from the oscilloscope to the PC, and one measurement data was lost.

The second attachment shows the histogram of the histogram of the estimated cavity pole frequencies.
I admit that there are not enough samples to treat it statistically.
Anyway, the mean and the standard deviation of the estimated frequencies are 47.6kHz and 2.4kHz.
Assuming a Gaussian distribution and zero systematic error, both of which are bold assumptions though, the result is 47.6(+/-0.6)kHz.

Now I removed the Pockels Cell from the RC input beam path.
I maximized the transmission by tweaking the steering mirrors and rotating the HWP.
Since the transmission PD was saturated without an ND filter on it, I reduced the VCO RF power slider to 2.85.
Accordingly, I changed the nominal common gain of the FSS servo to 10.5dB.
Attachment 1: RC_Ringdown_Estimates.png  192 kB  | Hide | Hide all
Attachment 2: Cavity_Pole_Histogram.png  44 kB  | Hide | Hide all
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