Numerical Quench Studies Of A Superconducting Dipole Magnet Based On Tilted Solenoids

Superconducting magnets have been widely applied in accelerators by the features of higher magnetic field,smaller magnet size,and better economic benefit.But quenching is a frustrating problem,which is an inevitable issue occurred when the superconductor properties above its critical-current surface during the superconducting magnet operation.The stored energy can be dissipated at the normal zone in a relatively short time within one second in the quench processing.This can cause overheating and voltage breakdown of superconducting coils,which might damage the magnet.Hence,quench protection and simulation for the superconducting magnet is very important,which can forecast the hot spot temperature,voltage and current decreasing and thus ensure the safety of the magnet in operating.Superconducting dipole based on tilted solenoid windings is a new concept of the magnet configuration.The advantages of this type magnet are as follows: high field quality in an extended dynamic range,no field optimization requirement,small number of components,simple and compact structure,small bore sizes not limiting “cos-theta” windings,and low processing cost.It is especially suitable for low cost superconducting accelerator magnets and ion-beam cancer therapy gantries.This type magnet is also chosen as an alternative option for the High Intensity heavy ion Accelerator Facility(HIAF).Due to special configuration of strands,conventional quench simulation method is not suitable for them.Therefore,this paper developed a computer program and take an experiment to study the quench propagation process.The main research contents are list as follows:(1)Based on logical coordinate system and Wilson method,we developed a quench processing model of the superconducting tilted solenoid and use Mathematica for simulating.The coil characteristic behavior such as hot spot temperature and voltage distributions after a quench have been obtained,they are different from the densely packed coils,which can give some references for the design of its quench protection system.(2)To study the quench process,we have designed,built and tested a superconducting tilted solenoid.A set of data acquisition system based on cryogenic Dewar and data collection was built.The data that use a heater to trigger quench when the magnet at liquid helium temperature was collected,so based on it,the longitudinal and transverse propagation velocity have been calculated.