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Entry  Fri Jul 9 20:16:19 2010, rana, Summary, PSL, Things I did to the PSL today: Refcav, PMC, cameras, etc. 
    Reply  Sun Jul 11 20:11:48 2010, rana, Summary, PSL, RC trend after the insulation removal rc.png
       Reply  Thu Jul 15 19:27:04 2010, rana, Summary, PSL, RC trend after the insulation removal Untitled.pnga.pngb.png
    Reply  Mon Jul 12 14:22:36 2010, Jenne, Summary, PSL, Things I did to the PSL today: Refcav, PMC, cameras, etc. 
Message ID: 3189     Entry time: Fri Jul 9 20:16:19 2010     Reply to this: 3190   3196
Author: rana 
Type: Summary 
Category: PSL 
Subject: Things I did to the PSL today: Refcav, PMC, cameras, etc. 

I re-aligned the beam into the PMC. I got basically no improvement. So I instead changed the .LOW setting so that PMCTRANS would no longer go yellow and make the donkey sound.

I did the same for the MOPA's AMPMON because its decayed state is now nominal.

 

Steve and I removed the thermal insulation from around the reference cavity vacuum chamber. It wasn't really any good anyways.

Here are the denuded photos:

 

Steve and I are now planning to replace the foam with some good foam, but before that we will wrap the RC chamber with copper sheets like you would wrap a filet mignon with applewood bacon.

This should reduce the thermal gradients across the can. We will then mount the sensors directly to the copper sheet using thermal epoxy. We will also use copper to cover most of this hugely

oversized window flange - we only need a ~1" hole to get the 0.3 mm beam out of there.

 

My hope is that all of this will improve the temperature stability of this cavity. Right now the daily frequency fluctuations of the NPRO (locked to the RC) are ~100 MHz. This implies

that the cavity dT = (100 MHz) / (299792458 / 1064e-9) / (5e-7) = 1 deg.    That's sad....

 

I also changed the RC_REFL cam to manual gain from AGC. I cranked it to max gain so that we can see the REFL image better.

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