High-sensitivity cooled coil system for nuclear magnetic resonance in kHz range

Lin, Tingting; Lin, Jun; Zhang, Yi; Lee, Yong-Ho; Zhao, Jing; Krause, Hans-Joachim

doi:10.1063/1.4901964

Journal Article

FZJ-2014-06223

High-sensitivity cooled coil system for nuclear magnetic resonance in kHz range

Lin, T. ; Zhang, Y.FZJ* ; Lee, Y.-H. ; Krause, H.-J.FZJ* ; Lin, J. ; Zhao, J. (Corresponding Author)

2014
American Institute of Physics [S.l.]

Review of scientific instruments 85(11), 114708 (2014) [10.1063/1.4901964]

This record in other databases:

Please use a persistent id in citations: http://hdl.handle.net/2128/16749 doi:10.1063/1.4901964

Abstract: In several low-field Nuclear Magnetic Resonance (LF-NMR) and surface nuclear magnetic resonance applications, i.e., in the frequency range of kHz, high sensitivity magnetic field detectors are needed. Usually, low-T c superconducting quantum interference devices (SQUIDs) with a high field sensitivity of about 1 fT/Hz1/2 are employed as detectors. Considering the flux trapping and operational difficulties associated with low-T c SQUIDs, we designed and fabricated liquid-nitrogen-cooled Cu coils for NMR detection in the kHz range. A cooled coil system consisting of a 9-cm diameter Cu coil and a low noise preamplifier was systematically investigated and reached a sensitivity of 2 fT/Hz1/2 at 77 K, which is 3 times better compared to the sensitivity at 300 K. A Q-switch circuit as an essential element for damping the ringing effects of the pickup coil was developed to acquire free induction decay signals of a water sample with minimum loss of signal. Our studies demonstrate that cooled Cu coils, if designed properly, can provide a comparable sensitivity to low-T c SQUIDs

Classification: