Title :
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
fDate :
6/1/1999 12:00:00 AM
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;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
