1. 3rd generation ITF sensitivity curve
Michele Punturo

2. EGO (FP6) curve
3rd generation curve “quickly” (and dirty) generated for the FP6 proposal
No signal recycling
Quantum locking “a la Heidmann”:
One additional control cavity per mirror
Squeezing added “ad hoc”
No real evaluation of the suspension requirements

3. R.Flaminio talk at the Gran Sasso meeting
More detailed study based on the keywords:
10km
Silicon
116kg 5K
Very preliminary and
driven by the goal

4. Cryogenic Payload Mirror Geometry: R=0,2m h=0,4m M=116kg
Laser power=2/2 kW, Recycling factor = 100
Finesse=600, Power in the cavities = 19MW
absorption  2+19W to extract (substrate,1ppm/cm+coating, 1ppm)
L≈0.70m, k(5K)≈423WK-1m-1
Constrain on the silicon ribbons:
a/b=0.1 (Dilution factor)
BreakStrength=2.6GPa
a=0.23mm, b=2.3mm
Constrain on the silicon ribbons:
a=5mm, b=50.mm

5. Optical Design Power & signal recycled interferometer Gaussian Beam
Waist 6 cm on the input & end mirrors
Coating loss angle 2×10-4

6. 3rd generation sensitivity

7. Conclusions
Pendulum and Mirror thermal noises are no more limiting the sensitivity
It could be better to relax the design requirements
Violin Modes start to play a relevant role
Optical readout noise is the dominant one
Heavier mirrors?
More cleaver ideas?
Squeezing?