Optimization of Support System for FAIR Energy Buncher Dipole Magnet

In superconducting magnets, the coils are placed inside a helium chamber and suspended from the outer vacuum chamber using supports. Many superconducting magnets, currently under operation, use support links with intermediate temperature intercepts to reduce the heat leak to the helium system. The support links for large superconducting magnets, required for spectrometry, need to provide excellent alignment of the coils with respect to the yoke after cooldown and magnet energization to achieve high magnetic field qualities. Optimization of such support system requires detailed design analysis of the entire structure using finite-element method software. This paper presents an analytical model for studying the effect of support stiffness over its performance after cooldown and magnet energization. Higher stiffness of the supports ensures that the coil movement is less under magnetic force. On the other hand, higher stiffness results in higher conduction heat load to helium. This study tries to find out the most suitable value of support stiffness that ensures both the conditions—less movement of coil and less conduction heat load to helium. Optimization of the support system for a large spectrometer magnet of FAIR, Germany is presented here using this model. This study shows that this model also finds the instability region of the support system where any small movement of the coil results in uncontrollable deformation. In addition, the results show that the initial alignment of the coil is another important parameter to achieve the desired coil alignment after energization and how this can be achieved at different magnet excitation levels.