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The displacement of the left mirror is ~0.2 nm. So the sensitivity of the cavity length to vertical acceleration is 4 x 10^-10 (dL/L) / g. Next we have to consider the limited vibration isolation characteristics of the reference cavities stack and spring pendulum. <<ImageLink(refcav1.png,Sag from Gravity,height=300)>> <<ImageLink(refcav1-zoom.png,Zoomed color scale,height=300)>> <<ImageLink(refcav1-zoom2.png,Zoom on one end,height=300)>> |
We have done some analysis of the Reference Cavity using COMSOL. We got the design parameters for the reference cavity from ???
Basic Model Parameters
T = 273 + 38 K (reference cavity can is kept at 38 C)
- Spacer and mirrors made of Corning Fused Silica (7940) - in reality its probably 7980?
Uses: Structural Mechanics module, Heat Transfer module, & Materials Library
Eigenmodes
- Remove gravity
- No constraints (as if there's no wire)
Vertical Sensitivity
- Constrain the grooves on the bottom in all 3 DOF.
- Add a load force on the spacer. F/V = -9.81 * 2200 (comsol likes a force/volume)
Deformation of the cylinder shows the actual shape. Color indicates displacement along the cavity axis.
The displacement of the left mirror is ~0.2 nm. So the sensitivity of the cavity length to vertical acceleration is 4 x 10^-10 (dL/L) / g. Next we have to consider the limited vibration isolation characteristics of the reference cavities stack and spring pendulum.
