Ultra-Lightweight Carbon Foam for Future Collider Tracking Detectors

Low-mass, ultra-stable particle tracking detectors will be critical elements of upgrades to experiments at the Large Hadron Collider (CERN) and at potential future electron-positron colliders. Mass assigned to support structures, although critical in function, compromises detection through production of secondary particles, which interfere with particle tracking. This SBIR focuses on sandwich core materials being used in detector support structures. Our objective is to reduce core-structure foam mass potentially by a factor of 5 or more. This will require new, innovative and entirely different foam processing. The process method proposed will lead to a hollow foam ligament, with ligament shell material composed solely of high conductivity graphite. Allcomp will investigate a new foam process that creates foam with hollow ligaments, where the ligaments comprise highly thermally conductive graphite. The graphite ligament material is over 4 times the conductivity of copper. A preliminary target for this Phase I demonstration, assuming a core thickness of 4.8mm, would be a radiation length of 0.05 % (of carbon) for the foam. This technology is pushing the envelope in carbon-foam processing particularly when one considers achieving this goal in large scale blocks. However, if successful, it would provide a lower mass alternative for future pixel and silicon strip tracker support/cooling structures for future collider tracking detectors. Modeling techniques developed by Allcomp to describe properties for solid ligament geometry will be used as an initial basis for describing the new hollow foam ligament behavior. With this approach in hand we will begin the process of seeking analytical modifications to describe foam thermal conductivity and foam stiffness. FE modeling of a typical detector sandwich structure is planned. Commercial Applications and Other Benefits: Light weight conductive graphite foam is an enabling material for the next generation extremely lightweight detectors for high energy physics experiments being conducted at CERN and many laboratories around the world. Hollow, low mass graphitic foam is under evaluation for advanced cathodes for batteries. Advanced high performance heat exchanger and energy storage devices for industry, aerospace, nuclear and power generation, power storage, and many other applications can be developed using graphite foam. As an example, researchers at the Oak Ridge National Laboratory (ORNL) are proposing to harness energy from the temperature gradient in tropical waters using heat exchanger made of graphitic foam.