Nuclear Techniques ›› 2020, Vol. 43 ›› Issue (1): 10201-010201.doi: 10.11889/j.0253-3219.2020.hjs.43.010201


Dynamic magnetic measurements of a Kicker magnet for a proton therapy facility

Guanqun HAN Wenjie QIN Bin LIU Xu CHEN Qushan LI   

  1. Institute of Applied Electromagnetic Engineering, Huazhong University of Science & Technology, Wuhan 430074, China
  • Received:2019-10-21 Revised:2019-11-23 Online:2020-01-15 Published:2020-01-21
  • Supported by:
    National Key Research and Development Plan for the 13th Five-year Plan(2016YFC0105305);National Natural ScienceFoundation of China(11975107)

Abstract: Background

A proton therapy facility based on superconducting cyclotron is under development in Huazhong University of Science and Technology Proton Therapy Facility (HUST-PTF). In HUST-PTF system, a kicker magnet upstream of the degrader is used to realize the fast switch on/off for the spot scanning process and the treatment safety.


This study aims to measure the integral field and the dynamic performance of the kicker magnet and implement a magnetic measurement system based on induction method.


First of all, two different schemes (long coil and PCB coil) were adopted in the magnetic measurement system to obtain the induced voltage. Then, the induction voltage signals acquired by induction coils were integrated by analog or digital integrators. Experimental data analysis was performed to evaluate these two schemes, and final solution for magnetic measurement system was determined.


Experimental results show that PCB coils with high geometric accuracy and RC integrators, less sensitive to zero drift, hence are adopted as the final solution of the measurement system. The overall error of the magnetic measurement system is less than 0.1%. The experimental results show that response time is less than 100 μs, the integral field greater than 0.025 2 T·m, integral field uniformity is better than 1%, and maximum standard deviation of uniformity is 0.006%.


The kicker magnet and its measurement system meet the design specifications.

Key words: Kicker magnet, Integral magnetic field, Dynamic performance, RC integrator, PCB coils

CLC Number: 

  • TL503.8