1. Open discussion: a) moving toward finalization of the ET conceptual design
We need to progress step by step
the mirror mass (~150 kg)
the material of the bulk (silicon)
The fiber material (silicon crystal thin rods/ aluminum /niobium)
Coating material choice
Coating procedure (standard vs no standard)
Optical performances ( total absorption)
Heat load and working Temperature
Geometry of the last stage suspension
Control strategy and related noise issue
Actuators and local sensing
Upper suspension geometry
Thermal issues along the chain and at the payload interface
Newtonian coupling including the effect at the interface of the last stage

2. The agenda of the WG2 session in Erice
Main topics
-Suspension upper part
- suspension lower part
- bulk properties
- coating properties
- actuator sensors
- cooling issues
…………………………………

3. Setting up a calendar for the next meetings
The paradigm: we call for meetings in anticoincidence with LVC ( ~ 1month of itme window)
Date
November 2009
February 2010
April/May 2010
July 2010
November 2010
February 2011
April/May 2011
July 2011
November 2011

4. Finding the location for new meetings
Jena, Germany
Glasgow, Scotland (?)
Trento/Padova, Italy (?)
Hannover , Germany (?)
CERN, Switzerland (???) /Giessen, (Germany) (???)
Nikhef, Netherland (?)
Lyon, (France) (?)
Napoli, (Italy) (?)
XXXXXXXXXXXXXXXX