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Message ID: 313     Entry time: Fri Aug 27 20:08:56 2010
Author: tarac 
Type: Notes 
Category: NoiseBudget 
Subject: COMSOL 

  I use COMSOL to simulate the temperature distribution inside the mirror. 

The mirrors are separate into 3 regions for different meshing quality see attached figures.

This model assume 0.95 emissivity on the surface, and 310 K at the surface between the mirror and the spacer.

The temperature between 10 mW and 10mW + RIN*10mW is plotted and fitted with polynomial function of order 9.

*the unit of y axis on fig3 is Kelvin

The Temperature difference will be applied to the coating surface and calculated the upper limit for photo thermal noise. 

The function is

 

T = p1*z.^9 + p2*z.^8 + p3*z.^7 + p4*z.^6 + 

    p5*z.^5 + p6*z.^4 + p7*z.^3 +

    p8*z.^2 + p9*z + p10;

 
where

 

 

       p1 =  -5.335e-10 ; %(-5.806e-10, -4.864e-10)

       p2 =   1.602e-08 ;% (1.474e-08, 1.731e-08)

       p3 =  -2.041e-07 ;% (-2.188e-07, -1.894e-07)

       p4 =   1.438e-06 ;% (1.347e-06, 1.528e-06)

       p5 =  -6.144e-06  ;%(-6.47e-06, -5.818e-06)

       p6 =   1.645e-05  ;%(1.576e-05, 1.715e-05)

       p7 =  -2.773e-05  ;%(-2.858e-05, -2.687e-05)

       p8 =   2.912e-05  ;%(2.857e-05, 2.967e-05)

       p9 =  -1.893e-05  ;%(-1.908e-05, -1.877e-05)

       p10 =   7.548e-06 ;% (7.534e-06, 7.562e-06)

 

 

 

Attachment 1: mesh.png  163 kB  | Hide | Hide all | Show all
mesh.png
Attachment 2: tz.png  36 kB  | Hide | Hide all | Show all
tz.png
Attachment 3: compare.png  10 kB  | Hide | Hide all | Show all
compare.png
Attachment 4: res_1mm.png  10 kB  | Show | Hide all | Show all
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