中国物理B ›› 2016, Vol. 25 ›› Issue (6): 68501-068501.doi: 10.1088/1674-1056/25/6/068501

• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

An efficient calibration method for SQUID measurement system using three orthogonal Helmholtz coils

Hua Li(李华), Shu-Lin Zhang(张树林), Chao-Xiang Zhang(张朝祥), Xiang-Yan Kong(孔祥燕), Xiao-Ming Xie(谢晓明)   

  1. 1 State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2015-12-02 修回日期:2016-01-31 出版日期:2016-06-05 发布日期:2016-06-05
  • 通讯作者: Shu-Lin Zhang E-mail:zhangsl@mail.sim.ac.cn
  • 基金资助:

    Project supported by the “Strategic Priority Research Program (B)” of the Chinese Academy of Sciences (Grant No. XDB04020200) and the Shanghai Municipal Science and Technology Commission Project, China (Grant No. 15DZ1940902).

An efficient calibration method for SQUID measurement system using three orthogonal Helmholtz coils

Hua Li(李华)1,2, Shu-Lin Zhang(张树林)1, Chao-Xiang Zhang(张朝祥)1, Xiang-Yan Kong(孔祥燕)1, Xiao-Ming Xie(谢晓明)1   

  1. 1 State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2015-12-02 Revised:2016-01-31 Online:2016-06-05 Published:2016-06-05
  • Contact: Shu-Lin Zhang E-mail:zhangsl@mail.sim.ac.cn
  • Supported by:

    Project supported by the “Strategic Priority Research Program (B)” of the Chinese Academy of Sciences (Grant No. XDB04020200) and the Shanghai Municipal Science and Technology Commission Project, China (Grant No. 15DZ1940902).

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摘要：

For a practical superconducting quantum interference device (SQUID) based measurement system, the Tesla/volt coefficient must be accurately calibrated. In this paper, we propose a highly efficient method of calibrating a SQUID magnetometer system using three orthogonal Helmholtz coils. The Tesla/volt coefficient is regarded as the magnitude of a vector pointing to the normal direction of the pickup coil. By applying magnetic fields through a three-dimensional Helmholtz coil, the Tesla/volt coefficient can be directly calculated from magnetometer responses to the three orthogonally applied magnetic fields. Calibration with alternating current (AC) field is normally used for better signal-to-noise ratio in noisy urban environments and the results are compared with the direct current (DC) calibration to avoid possible effects due to eddy current. In our experiment, a calibration relative error of about 6.89×10-4 is obtained, and the error is mainly caused by the non-orthogonality of three axes of the Helmholtz coils. The method does not need precise alignment of the magnetometer inside the Helmholtz coil. It can be used for the multichannel magnetometer system calibration effectively and accurately.

关键词: SQUID, magnetometer, Tesla/volt coefficient calibration, three-dimensional Helmholtz coil

Abstract:

For a practical superconducting quantum interference device (SQUID) based measurement system, the Tesla/volt coefficient must be accurately calibrated. In this paper, we propose a highly efficient method of calibrating a SQUID magnetometer system using three orthogonal Helmholtz coils. The Tesla/volt coefficient is regarded as the magnitude of a vector pointing to the normal direction of the pickup coil. By applying magnetic fields through a three-dimensional Helmholtz coil, the Tesla/volt coefficient can be directly calculated from magnetometer responses to the three orthogonally applied magnetic fields. Calibration with alternating current (AC) field is normally used for better signal-to-noise ratio in noisy urban environments and the results are compared with the direct current (DC) calibration to avoid possible effects due to eddy current. In our experiment, a calibration relative error of about 6.89×10-4 is obtained, and the error is mainly caused by the non-orthogonality of three axes of the Helmholtz coils. The method does not need precise alignment of the magnetometer inside the Helmholtz coil. It can be used for the multichannel magnetometer system calibration effectively and accurately.

Key words: SQUID, magnetometer, Tesla/volt coefficient calibration, three-dimensional Helmholtz coil

中图分类号:  (Superconducting quantum interference devices (SQUIDs))

  • 85.25.Dq
07.55.Ge (Magnetometers for magnetic field measurements) 06.20.fb (Standards and calibration) 07.55.Db (Generation of magnetic fields; magnets)