1. Cylinders or Space Frames ? David Hitlin September 16, 2005

2. David Hitlin Sept. 16, 2005 2 Alternatives to rohacell shells  Tensioned fibers (JA)  Light carbon fiber space frame (DH) More material than naïve tension system, but more than shells  Still much less than silicon+cables+cooling Should be very rigid and self-supporting Facitates gas cooling Permits use of lampshade endcaps  Used in B A B AR vertex detector (much smaller scale)  Greatly reduces area of silicon to cover a given solid angle  Reduces multiple scattering by increasing average andle of incidence for charged particles  Facilitates access

3. David Hitlin Sept. 16, 2005 3 http://f.home.cern.ch/f/feofilov/public/TDR-HTM/its1-1.htm ALICE uses carbon fiber space frames

4. David Hitlin Sept. 16, 2005 4

5. 5 An example configuration

6. David Hitlin Sept. 16, 2005 6 First shot at a 2D finite element analysis

7. David Hitlin Sept. 16, 2005 7 Components  Hollow tubes  Molded ferrules …………

8. David Hitlin Sept. 16, 2005 8 Next  Optimize a 2D planar structure  Extend to a 3D cylinder and a conical endcap  Detail design Mounting, handling of silicon modules Potential integration of cooling into structural tubes Cable routing Mounting structures  Explore fabrication methods