Thermo-mechanical design of a DTL tank

This study describes the design of a short DTL (Drift Tube Linac) tank model for the IPHI project, whose thermal, mechanical and technological characteristics can be extrapolated to a complete 6-meter machine. We compared the mechanical properties, weldability and ultra-high vacuum compatibility of different base materials, and selected only stainless steel. Steel was rejected as it is more difficult to guarantee the reproducibility of its properties in ultra-high vacuum. It is nevertheless a possible choice. Analytical calculations have enabled us to scan different configurations and define orders of magnitude. The 3D calculations confirm these values and consolidate the design of highly 3D structures. In particular, we have verified that the design of the prototype's main openings is compatible with acceptable mechanical constraints. The addition of a layer of thermally conductive material significantly improves cooling and minimizes stress. The material chosen for this thermal layer is copper, deposited by electrolysis. This choice has implications for the length of the segments of the future DTL. Finally, pressurizing the enclosure is unlikely to generate any disturbing frequency drift. The model designed is mechanically viable, and the power tests to be carried out at CERN will validate the concepts for a complete future DTL