The first proton NMR imaging of ice: stray-field imaging and relaxation studies.

A proton magnetic resonance image of ice was observed with the stray-field (STRAFI) technique. A preliminary study of proton relaxation times was performed in water and ice, at different temperatures. For example, a value of 3.5 micros for the spin-spin relaxation time, T(2), was found in ice at 258 K. Such a short T(2) value leads to significant signal loss, as compared to liquid water, and to a shortening of the STRAFI echo-trains. In particular, a STRAFI signal for protons in ice could be observed only at echo times as short as 15 and 25 micros, for RF pulse durations corresponding to 90 degrees and 50 degrees magnetisation tip angles, respectively. This behaviour is in contrast with that of deuteriated water. Imaging ice, as shown here, opens new prospects in studies involving environmental and materials science, for example.