Magnetic field test of superconducting coils for the compact proton therapy cyclotron

The superconducting cyclotron for proton therapy that is under design by ASIPP (Hefei, China) and JINR (Dubna, Russia) will be able to accelerate protons to the energy 200 MeV with the maximum beam current of 1 mu A. The performance of superconducting magnets is the key to the superconducting cyclotron, and it will directly affect the quality of the proton beam and the therapeutic effect. To measure the magnetic induction intensity of the superconducting coil with the cryogenic Hall probes on the testing platform. As the current has been increased from 0 to 160 A, the measurement error of probes decreases obviously whose tendencies are consistent. By comparing the measuring results with the theoretical results, we can confirm the quality of superconducting coil and the installation location. Meanwhile, the basic operation of cryogenic Hall probes and data acquisition system is grasped, and the experimental experience for the magnetic intensity test of superconducting cyclotron has been accumulated.