High-T/sub c/ SQUIDs for low-field NMR and MRI of room temperature samples

Author

Schlenga, K. ; McDermott, R.F. ; Clarke, J. ; De Souza, R.E. ; Annjoe Wong-Foy ; Pines, A.

Author_Institution

Div. of Phys., Lawrence Berkeley Nat. Lab., CA, USA

Volume

9

Issue

2

fYear

1999

fDate

6/1/1999 12:00:00 AM

Firstpage

4424

Lastpage

4427

Abstract

We have constructed a high-T/sub c/ SQUID spectrometer to detect NMR signals from samples at room temperature in magnetic fields up to 3 mT. The multiloop SQUID magnetometer has a system noise of about 30 fT/Hz/sup 1/2/ at the relevant frequencies of 2 to 100 kHz. The magnetometer is operated in vacuum at 77 K, and is separated from the sample, which Is less than 1.5 mm away, by a sapphire window. In a magnetic field of 2 mT we can detect the proton spin echo at 86 kHz without signal averaging. This sensitivity enables us to obtain one-dimensional images. In addition, we present data on hyperpolarized /sup 129/Xe, which has an optically pumped polarization of several percent.

Keywords

NMR imaging; NMR spectrometers; SQUID magnetometers; high-temperature superconductors; 2 to 100 kHz; 2 to 3 mT; MRI; NMR; high-T/sub c/ superconductor; hyperpolarized /sup 129/Xe; multiloop SQUID magnetometer; one-dimensional image; optically pumped polarization; proton spin echo; room temperature sample; spectrometer; Frequency; Magnetic fields; Magnetic noise; Nuclear magnetic resonance; Optical pumping; Protons; SQUID magnetometers; Signal detection; Spectroscopy; Temperature;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.784006

Filename

784006