The Simulation And Study Of MICE Superconduction Magnet Cooling And Quench Process

The experiment device of Muon ionization cooling is the world’s first experimentaldevice to proof ionization cooling of muons. MICE superconducting coupling magnet isone of the key equipment in muon ionization cooling experiment. Before assemblyMICE superconducting coupling magnet needs to be tested offline. MICEsuperconducting test magnet has been finished now. The diameter is the same as thesuperconducting coupling magnet, but the thickness of the coil is a quarter of MICEcoupling magnet. What we need to do is to cool the magnet, load current and quenchtest. The fabrication process of MICE superconducting magnet and the reliability ofsuperconducting magnet test system also need to be proved. And provide a reliableguarantee for the further of the MICE prototype coil manufacturing and cooling test.The work of this paper includes:The current lead for superconducting magnets is optimized by theoretical analysis.Then the optimized current lead is simulated by ANSYS CFX under the conditions withor without gas cooling. The method to calculate the thermal load of the vacuummultilayer insulation and the magnet supporting structure are presented. The heat loadof the MICE superconducting magnet is determined.The numerical simulation is conducted to the magnet cooling process in twodifferent methods, the open cycle and the close cycle. The temperature distribution ofthe magnet is analyzed and the cooling curves of magnet cooling are presented. Thenthe C type cooling method is simulated and analyzed in detail. The cooling process ofthis cooling method has optimized. The optimized relationship between the flow ofhelium and the magnet temperature is obtained. All these provide the basis for themagnet cooling test.The system pressure changing with time after quench has been simulated. Throughthe analysis of simulation the conclusion can be obtained. In order to achieve the heliumrecovery, increase the buffer capacity or reducing the volume of liquid helium caneffectively reduce the system pressure after quench.The MICE superconducting magnet cooling test has been done. And theexperimental results are compared with the simulation results. At the same time, themain reason why the temperature on the magnet surface is not the predicted temperature is analyzed.