Authors: S Hartwig H H Albrecht H J Scheer M Burghoff L Trahms
Publish Date: 2012/09/13
Volume: 44, Issue: 1-2, Pages: 9-22
Abstract
We describe a superconducting quantum interference device SQUIDbased nuclear magnetic resonance NMR spectrometer operating at ultralow magnetic fields far below the Earth’s field The spectrometer consists of a heliumcooled magnetic sensor system and two Helmholtz coils one for prepolarizing the sample by fields of up to 5 mT and one for the detection in fields of the nanotesla and microtesla range The spectrometer represents the current state of the art in ultralowfield NMR and enables the observation of phenomena that are difficult or impossible to achieve by a conventional NMR setting In particular one can obtain broad band spectra covering different nuclei such as 1H and 31P with a frequency resolution in the millihertz range observe the variation of their heteronuclear coupling with the detection field strength and investigate relaxation processes that reflect molecular dynamics in the millisecond range
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