• HTS SQUID-based Low-field NMR
  • Low applied magnetic field ~1 Gauss
  • T1 and T2 measurement
  • HTS SQUID Sensor
  • Easy Operation & Maintenance
  • With pre-polarization field ~ 500 Gauss
  • With field compensation module

In order to achieve high-sensitivity in the detection of weak magnetic signals, the sensitive superconducting quantum interference device (SQUID) is used for NMR detector.

SQUID is a very sensitive magnetometer for extremely weak magnetic fields, based on superconducting loops containing Josephson junctions.


Most SQUID-detected low field NMR systems are set up in magnetically shielded room (MSR). But the MSR require high cost and a large space. MagQu set up a compact and sensitive High-Tc SQUID-detected NMR spectrometer using flux coupling in microtesla field without MSR.

The measuring coil, pre-polarization coil, compensation coils, and gradient coils are set up inside a miniature radio frequency shielded box (RFSB); the SQUID sensor is shielded with a superconducting vessel and installed in a liquid nitrogen cryostat that is seated in a compact magnetically shielded cylinder (MSC). The dimension of the RFSB was 1 m x 1 m x 0.6 m; the MSC is 60 cm in diameter and 70 cm in height. The NMR signals of samples are inductively coupled to the high-Tc SQUID magnetometer via magnetic flux transformer.



  1. Hsin-Hsien Chen, Kai-Wen Huang*, Hong-Chang Yang, Herng-Er Horng, and Shu-Hsien Liao*” Optimization of the detection coil of high-Tc superconducting quantum interference device-based nuclear magnetic resonance for discriminating a minimum amount of liver tumor of rats in microtesla fields” , J. Appl. Phys. 114, 064701 (2013).
  2. S.H. Liao, H.H. Chen, Y.S. Deng, M.W. Wang, K.L. Chen, C.W. Liu, C.I. Liu, H.C. Yang, H.E. Horng, J.J. Chieh, and S.Y. Yang, “Microtesla NMR and high resolution MR imaging using high-Tc SQUIDs”, IEEE Trans. Appl. Supercond. 23, 1602404 (2013).
  3. K.W. Huang, H.H. Chen, H.C. Yang, H.E. Horng, S.H. Liao, J.J. Chieh, and S.Y. Yang, “Use of a high-Tc SQUID-based nuclear magnetic resonance spectrometer in magnetically unshielded environments to discriminate tumors in rats, by characterizing the longitudinal relaxation rate”, JINST 7, 6005 (2012).
  4. Shu-Hsien Liao, Chieh-Wen Liu, Hong-Chang Yang, Hsin-Hsien Chen, Ming-Jye Chen, Kuen-Lin Chen, Herng-Er Horng, Li-Min Wang, and Shieh-Yueh Yang, “Spin-spin relaxation of protons in ferrofluids characterized with a high-Tc superconducting quantum interference device-detected magnetometer in microtesla fields”, Appl. Phys. Lett. 100, 232405 (2012).
  5. Hong-Chang Yang, Chieh-Wen Liu, S.H. Liao, Hsin-Hsien Chen, M.J. Chen, K.L. Chen, Herng-Er Horng, S.Y. Yang, and L.M. Wang, “Temperature and concentration-dependent relaxation of ferrofluids characterized with a high-Tc SQUID-based nuclear magnetic resonance spectrometer”, Appl. Phys. Lett. 100, 202405 (2012).
  6. Hsin-Hsien Chen, Hong-Chang Yang, Herng-Er Horng, Shu-Hsien Liao, Shieh Yueh, and Li-Min Wang, “A compact SQUID-detected magnetic resonance imaging system under microtesla field in a magnetically unshielded environment”, J. Appl. Phys. 110, 093903 (2011).
  7. Shu-Hsien Liao, Kai-Wen Huang, Hong-Chang Yang, Chang-Te Yen, M. J. Chen, Hsin-Hsien Chen, Herng-Er Horng, and Shieh Yueh Yang, “Characterization of tumors using high-Tc superconducting quantum interference device-detected nuclear magnetic resonance and imaging”, Appl. Phys. Lett. 97, 263701 (2010)
Magnetic field strength
1 Gauss
Magnetic field in-homogeneity
< 0.05 % in 2 x 2 x 2 cm3 /< 0.1 % in 3 x 3 x 3 cm3
Signal to noise ratio
>20 for 2 ml water
Max. Sample size
3 x 3 x 3 cm3
Electro-magnetic shielding factor
40 dB @ 4 kHz
Liquid nitrogen tank
10 L
Noise of HTS dc SQUID sensor
< 200 fT/Hz^(1/2) @ 1000Hz
Ordering information:
Catalog Number Description Package Size
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  • Applications Content: 
    Rapid diagnosis for tumor biopsy
  • Applications Content: 
    Nutrition analysis for foods