Free precession and transverse relaxation of hyperpolarized 129Xe gas detected by SQUIDs in ultra-low magnetic fields
Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
Corresponding author: a email@example.com
Revised: 21 December 2006
Published online: 9 February 2007
We studied the free precession of the nuclear magnetization of hyperpolarized 129Xe gas in external magnetic fields as low as B0 = 4.5 nT, using SQUIDs as magnetic flux detectors. The transverse relaxation was mainly caused by the restricted diffusion of 129Xe in the presence of ambient magnetic field gradients. Its pressure dependence was measured in the range from 30 mbar to 850 mbar and compared quantitatively to theory. Motional narrowing was observed at low pressure, yielding transverse relaxation times of up to 8000 s.
PACS: 82.56.Na – Relaxation / 82.56.Lz – Diffusion / 51.20.+d – Viscosity, diffusion, and thermal conductivity / 85.25.Dq – Superconducting quantum interference devices (SQUIDs)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007