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Entry  Thu Oct 9 16:31:53 2014, ericq, Update, LSC, CARM W/N TFs carm2SQRTinv.pdfcarm2REFLDC.pdf
    Reply  Thu Oct 9 18:30:59 2014, Jenne, Update, LSC, CARM W/N TFs 6x
       Reply  Fri Oct 10 00:20:37 2014, rana, Update, LSC, CARM W/N TFs carm40.pngcarm.pdf
          Reply  Wed Oct 15 02:59:04 2014, rana, Update, LSC, CARM W/N TFs spring.pdfantispring.pdf
             Reply  Thu Oct 16 22:35:05 2014, rana, Update, LSC, CARM W/N TFs carm_spring.pdfcarm_antispring.pdf
       Reply  Wed Oct 15 13:38:33 2014, Jenne, Update, LSC, CARM W/N TFs 7x
          Reply  Mon Oct 20 17:50:30 2014, Jenne, Update, LSC, CARM W/N TFs (Others were all wrong!) 7x
Message ID: 10589     Entry time: Thu Oct 9 16:31:53 2014     Reply to this: 10591
Author: ericq 
Type: Update 
Category: LSC 
Subject: CARM W/N TFs 

In my previous simulation results, I've always plotted W/m, which isn't exactly straightforward. We often think about the displacement that a given mirror actuator output will induce, but when we're locking the full IFO, radiation pressure effects modify the mechanical response depending on the current detuning, making the meaning of W/m transfer functions a little fuzzy.

So, I've redone my MIST simulations to report Watts of signal response due to actual actuator newtons, which is what we actually control with the digital system. Note, however, that these Watts are those that would be sensed by a detector directly at the given port, and doesn't take into account the power reduction from in-air beamsplitters, etc.

As an example, here are the SqrtInv and REFLDC CARM TFs for the anti-spring case:

carm2SQRTinv.pdfcarm2REFLDC.pdf

 

The units of the SqrtInv plot are maybe a little weird, these TFs are the exact shape of the TRX W/N TFs with the DC value adjusted by the ratio of the DC sweep derivatives of TRX and SqrtInv. 

All of the results live in /svn/trunk/modeling/PRFPMI_radpressure/

 

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