On Tuesday, February 23, 2016 at 1:09:35 PM UTC-5, Phil Hobbs wrote:   
   > On 02/22/2016 08:46 PM, RichD wrote:   
   > > I atended a presentation of the LIGO discovery last week,   
   > > by the lead engineer on the interferometry, the limiting   
   > > factor on the whole shebang   
   > >   
   > > At conclusion, he forecast a schedule of long term performance   
   > > improvements.  One of these, 10 years out, is the use of silicon,   
   > > or silicon oxide, mirrors.   
   > >   
   > > What's the advantage of this material?  And what are they using now?   
   > >   
   > > --   
   > > Rich   
   > >   
   >   
   > Probably that as a single crystal with a very low dislocation density,   
   > it should have essentially zero residual stress and hence zero creep.   
      
   Huh, I was visiting caltech ~2002-3? and talking with a staff/physics guy.   
   He runs advanced labs 1/2 time and works on ligo  1/2 time.  He said   
   one of the issue's was 1/f type noise due to thermal relaxations somewhere   
   in the mirror mounts... (or something like that.)   
      
   George H.   
   >   
   > Cheers   
   >   
   > Phil Hobbs   
   >   
   > --   
   > Dr Philip C D Hobbs   
   > Principal Consultant   
   > ElectroOptical Innovations LLC   
   > Optics, Electro-optics, Photonics, Analog Electronics   
   >   
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