Speaker
Description
Based on the measured [1] very low power loss of the HTS-based magnet of 0.4 T field in 10 mm beam gap and ramp rate of 300 T/s we outline the HTS-based accelerator magnet conceptual design for 2.0 T field in the 30 mm (V) x 150 mm (H) beam gap for the muon acceleration with ramp rates up to 1000 T/s. The arrangements of the magnetic core and the 72 kA HTS power cable are presented. The placement of HTS cable within the magnet core is optimized for the minimum magnetic field crossing its space. The supercritical helium of 5.5 K and 0.28 MPa is chosen for the HTS conductor coolant due to its high specific heat that allows for a strong minimization of cryogenic power loss. The numerical calculation of HTS cable hysteresis loss at 15 K (minimal available temperature of YBCO critical current vs external B-field) is scaled to the magnet operations at (5 - 10) K using the dependence of the YBCO critical current vs temperature [2]. The projected in this way HTS cable hysteresis power loss is 3.5 J/m for the 1000 T/s ramp rate within the +/- 1.7 T field linear response to the energizing current. With the helium coolant flow of 2.5 g/s, the projected cryogenic electric power is 4.6 kW/m at 5 Hz, indicating the power-wise economic feasibility of this HTS magnet for the muon acceleration.
[1] H. Piekarz et al., IEEE Trans. on Appl. Superconductivity, 32 (2022) 6, 4100404
[2] C. Senatore et al., Superconductivity. Sci. Technol. 29 (2016) 014002
