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Entry  Tue Aug 20 00:19:23 2013, rana, Update, LSC, PRMI / DRMI investigations 6x
    Reply  Tue Aug 20 01:28:47 2013, Jenne, Update, LSC, REFL investigations 
       Reply  Tue Aug 20 11:41:30 2013, Koji, Update, LSC, REFL investigations 
          Reply  Tue Aug 20 11:52:20 2013, Jenne, Update, LSC, REFL investigations 
             Reply  Tue Aug 20 18:42:57 2013, Jenne, Update, LSC, REFL investigations 
Message ID: 9038     Entry time: Tue Aug 20 01:28:47 2013     In reply to: 9037     Reply to this: 9040
Author: Jenne 
Type: Update 
Category: LSC 
Subject: REFL investigations 

According to the wiki, REFL 11 has a transimpedance of 4.08kV/A, and REFL 55 has a transimpedance of 615V/A.  This is a ratio of ~6.5 .  My optickle simulations from earlier this evening indicate that, at maximum, there is a ~factor of 2 more signal in REFL 11 than REFL 55.  This is a factor of order 10-15.  Then, REFL 55 has 15dB whitening gain, which is a factor of ~4.  So, this explains why we're seeing so much more digital signal on REFL11 than REFL55.

Tomorrow, I need to replace the 50/50 beam splitter that splits the beam between REFL55 and REFL11 (33 and 165 have already had their light picked off at this point).  I want to put in a 10% reflector, 90% transmission beamsplitter.  Steve, can you please find me one of these, and if we don't have one, order one? This will give us a little more light on 55, and less light on 11, so hopefully we won't be saturating things anymore.

 

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