A High Thermal Performance, Self-Contained Heat Extraction System suited to Highly Distributed Heat Sources, with Premise Based on Ultra-Lightweight Considerations

70080 Volumetric growth in present day pixel detectors, coupled with increased detector thermal heat load and attendant cooling system complexity, is presenting severe design and performance limitation to fulfilling the needs of precision tracking. The structural and cooling system designs found in these detectors compromise pixel tracking system precision by exceeding the performance limits set for structural mass. Non-structural mass, in the form of a large array of cooling lines and plumbing connections add to this mass penalty. In addition, a severe maintenance regimen will be required to service this very large array of pipes, regulators, and connectors¿all in a space that is largely inaccessible. This project will replace the coolant system with a high performance carbon-carbon heat-pipe technology. By limiting heat transfer to the circulating coolant at the heat pipe condenser end, the hundreds of required coolant inlet and returns would be reduced ten-fold. Phase I will adapt metallic heat-pipe technology to a carbon-carbon material. A compatible wick material will be developed, and thermal heat-pipe performance will be demonstrated for a heat load compatible with the ATLAS Pixel Detector. A conceptual design for implementing this concept in an ATLAS-like pixel detector will also be initiated. Phase II will complete the pipe/wick development and construct a Pixel-Detector-scale prototype for investigating thermal and stability performance. Commercial Applications and Other Benefits as described by the awardee: Metallic heat-pipes, e.g., with sintered or screen wicks are becoming more common in the electronics field. However, for applications involving silicon-based electronics or semiconductors detectors, a thermal expansion mismatch with the heat-pipe metallic housing has created stress problems. Also, in very high heat flux electronic applications, heat removal remains a serious issue. A low expansion coefficient heat-pipe would be a large benefit to the electronics industry and a number of military applications.