The HESR (High Energy Storage Ring), as an important part of the FAIR (Facility for Antiproton and Ion Research), contains, among other magnets, a number of 66 sextupole magnets used for chromaticity correction of the beam. These are normalconducting DC magnets, manufactured, tested and delivered to FAIR by the National Institute for Research and Development in Electrical Engineering ICPE-CA Bucharest. Knowledge of the fluidic and thermal behavior of normal-conducting magnets for particle accelerators, as well as a correct design of their cooling system are very important for obtaining optimal parameters in the operation of these magnets. Therefore, in this paper an analysis of the fluidic and thermal behavior of normal-conducting magnets was performed. This analysis highlighted the steps to be followed and the main parameters to be considered in the design process of the normal-conducting magnets cooling system. Also, the analysis aimed to determine the cooling fluid flow required to evacuate the heat dissipated on the magnet excitation circuit. Starting from the performed analysis, the total pressure losses on the HESR sextupole magnet cooling circuit were determined by analytical calculation, by numerical simulations and by measurements. To perform the measurements, a special test stand was developed, its structure and the measurements results being presented in the paper.

Keywords: Particle accelerator, Storage ring, Sextupole magnet, Cooling system, Heat transfer, Pressure loss, Pressure regulator, Coil design, Numerical simulation