Highly Sensitive Measurement of Moisture Content Using HTS-SQUID

Author

Tsukada, Keiji ; Kiwa, Toshihiko ; Tahara, Hideaki ; Miyake, Etsuro ; Yamada, Hironobu ; Tsukamoto, Akira ; Kandori, Akihiko

Author_Institution

Grad. Sch. of Natural Sci. & Technol., Okayama Univ., Okayama, Japan

Volume

19

Issue

3

fYear

2009

fDate

6/1/2009 12:00:00 AM

Firstpage

878

Lastpage

881

Abstract

We developed a highly sensitive magnetic system for measuring moisture content using an HTS-SQUID sensor. The system consists mainly of an exposure coil, a Dewar flask containing HTS-SQUID immersed in liquid nitrogen, a cancellation coil, a lock-in amplifier, magnetically shielded box, and FLL circuit. The cancellation coil was used to eliminate the applied magnetic field at the sensor position, and then a cancellation ratio of more than -40 dB was obtained. By the high performance, the subject can be exposed to a powerful magnetic field strength in the order of muT, and a weak magnetic signal of less than tens of pT from the subject can be detected. Using a magnetic vector analysis technique, more precise measurement of moisture content is realized.

Keywords

SQUIDs; high-temperature superconductors; magnetic sensors; moisture measurement; Dewar flask; FLL circuit; HTS-SQUID sensor; cancellation coil; exposure coil; liquid nitrogen; lock-in amplifier; magnetic field strength; magnetic vector analysis technique; moisture measurement; sensitive magnetic sensor; sensitive magnetic system; Diamagnetism; HTS-SQUID; magnetic cancellation; moisture content;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2009.2019659

Filename

5075618