2-D and 3-D Design of the Block-Coil Dipole Option for the Future Circular Collider

In the framework of the EuroCirCol project, the development of a conceptual design of the future circular collider main dipole is performed. The status of the block-coil option under investigation at CEA Saclay is presented. First, a two-dimensional (2-D) electromagnetic analysis is performed in a double aperture configuration with an interbeam separation of 250 mm. This is completed by a 3-D magnetic optimization, taking into consideration the analysis of the peak field value and position, as well as the coil ends integrated field quality. The main objective of the 3-D optimization is to keep coil ends as short as possible. The field quality optimization satisfies all requirements and leads to a peak field lower in the ends compared to the straight section. Finally, a 2-D mechanical study relying on a shell-based structure using bladders and keys is carried out. All main loading steps of the coils are taken into account.