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Thermal noise limit
Parameters needed for thermal noise calculation
| Description | Material | Parameter name | Value | Comment | |
|---|---|---|---|---|---|
| Boltzmann constant | kb | 1.38064852 × 10-23 m2 kg s-2 K-1 | |||
| Temperature (K) | T | 300 | |||
| Poisson Ratio of substrate | Fused Silica | σsb | 0.16 | Fused Silica substrtae [1] | |
| Poisson Ratio of coating | AlGaAs | σc | 0.32 | AlGaAs coating [2] | |
| Young's modulus of substrate | Fused Silica | Esb | 72.7 Gpa | Fused Silica substrtae [1] | |
| Young's modulus of spacer | ULE | Esp | 67.6 Gpa | ULE Spacer [1] | |
| Young's modulus of coating | AlGaAs | Ec | 100 Gpa | AlGaAs coating [2] | |
| Length of cavity | L | 0.48 m | Sr Beast [3] | ||
| Spacer radius | Rsp | 0.045 m | Sr Beast [3] | ||
| Central bore radius of spacer | rsp | 0.0065 m | Sebastian Häfner Thesis page 83 | ||
| Thickness of coating | AlGaAs | D | 6.83*10-6 m | AlGaAs coating [2] | |
| 1/e2 mode radius on the mirror | w | 0.000488 m for Mirror 1 0.000677 m for Mirror 2 | Mode calculations | ||
| Effective coefficient of thermal expansion for substrate | αsb | 1.2* 10-6 K-1 | Fused Silica substrtae [2] | ||
| Effective coefficient of thermal expansion for coating | αc | 1.68* 10-5 K-1 | AlGaAs coating [2] | ||
| Effective thermorefractive coefficient for coating | βc | 5*10-5 | AlGaAs coating [2] | ||
| Thermal conductivity for substrate | κsb | 1.38 W/Km | Fused Silica substrate [2] | ||
| Thermal conductivity for coating | κc | 62.9 W/Km | AlGaAs coating [2] | ||
| Heat capacity per unit volume for substrate | Csb | 1.71*106 J/Km3 | Fused Silica substrate [2] | ||
| Heat capacity per unit volume for coating | Cc | 1.64*106 J/Km3 | AlGaAs coating [2] | ||