• Optical_Platform_Suspension

Optical Platform Suspension

Each in-vacuum optical table for the 40 m test masses is an optical breadboard with a diameter of 38 inches. We plan to place a single stage suspended breadboard on top of this existing table to get 1 additional stage of seismic isolation. We will need 4 of these to cover each test mass.

• VOPO style suspension
  • Attach a structure (poles or a frame) on the existing breadboard
  • The structure supports vertical blades
  • Wires are attached on the vertical blades
  • A breadboard is suspended from the vertical blades
• Breadboard
  • Thickness
  • Internal resonances: modes/frequencies
• Blade spring
  • Load weight (total weight of the load, max load)
  • constrained layer damping of blade modes ?
  • What about just using 3 little coil springs to mount the breadboard from underneath rather than use blades? Then its more like an extra layer of the stack.
• Counter balance
• Vibration isolation
  • Requirement: 30x reduction for f = 10-100 Hz
  • pendular modes should be 0.2-0.45 Hz or 1.5-2.5 Hz to avoid SOS resonances.
• Active control
  • Sensor (What, how many, how sensitive, range, noise)
  • Actuators (Coil Magnet, requirement, strength, Vertical, Horizontal )
  • Electronics (Feedthru)
  • Control system
  • does it need to be active or can we use resonant eddy current damping?
• Utility structures
  • EQ stops
  • Safety (Blades/Wires)
• Active VS Passive approach
  • Active
    • Pros
      • ...
    • Cons
      • ...
  • Passive
    • Pros
      • ...
    • Cons
      • ...