Development of a HTS SQUID gradiometer system for the measurement of very weak magnetic field in an unshielded environment

비자기차폐환경에서 미세 자기장 측정을 위한 고온초전도 gradiometer 시스템의 개발

  • Kim, In-Seon (Korea Research Institiute of Standards and Science) ;
  • Kim, Jin-Mok (Korea Research Institiute of Standards and Science) ;
  • Park, Yong-Ki (Korea Research Institiute of Standards and Science)
  • 김인선 (한국표준과학연구원, 초전도그룹) ;
  • 김진목 (한국표준과학연구원, 초전도그룹) ;
  • 박용기 (한국표준과학연구원, 초전도그룹)
  • Published : 2000.08.16

Abstract

We have developed a YBCO SQUID gradiometer system for the measurement of a very weak magnetic field in an unshielded environment. The system consists of a SQUID gradiometer sensor, low noise pre-amp, and FLL(fluxlocked loop) control electronics. The gradiometer sensors have been fabricated on STO bicrystal substrates, and exhibit a magnetic noise of 300 fT/${\surd}$ Hz/cm at 100 Hz. The overall magnetic field noise of the SQUID gradiometer system was about 10 pT/${\surd}$ Hz/cm at 10 Hz without any magnetic shield. The system demonstrated a high stability for a long time, and real-time measurement resolution ${\le}$ 100 pT/cm in the unshielded environments.

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