Nuclear Techniques ›› 2015, Vol. 38 ›› Issue (7): 70103-070103.

• SYNCHROTRON RADIATION TECHNOLOGY AND APPLICATIONS •

### Integral magnetic field measurement of THz-FEL oscillator undulator based on stretch-wire method

WANG Yanbing LIU Xialing QIN Bin LIU Xu YANG Lei CHEN Wei LIU Kaifeng YANG Jun

1. (State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science & Technology, Wuhan 430074, China)
• Received:2015-01-15 Revised:2015-02-06 Online:2015-07-10 Published:2015-07-10
• Contact: Bin Qin E-mail:bin.qin@mail.hust.edu.cn
• Supported by:

National Natural Science Foundation of China

Abstract:

Background: In collaboration with the National Synchrotron Radiation Laboratory, Huazhong University of Science and Technology is developing an oscillator-based THz free-electron laser (HUST THz-FEL). Purpose: In order to measure the magnetic field integrals of the undualtor accurately and quickly, a measurement system based on the stretch-wire method (SWM) was established. Methods: In the system, an eight and a half digital multimeter, Agilent 3458, was adopted to acquire the micro-volt voltage signal, and a Kohzu high precision positioning platform was employed to realize the high synchronized wire movement. The software of this system was implemented by LabVIEW programming Results: The field measurement system was tested in a prototype hybrid permanent undulator with 7 periods, which shows consistent results with the Hall probe mapping. The repeatability precision for first integral and second integral are better than 2.5?10?6 T?m and 2.5?10?6 T?m2 respectively. Conclusion: The system met the design requirements and will be applied to the compact THz FEL oscillator located in Huazhong University of Science and Technology.

Key words: Undulator, SWM, Magnetic field integral