Cylinders or Space Frames ?

David Hitlin

September 16, 2005

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 BABAR 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

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

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David Hitlin Sept. 16, 2005 5

An example configuration

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First shot at a 2D finite element analysis

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Components Hollow tubes

Molded ferrules

…………

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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