K. Woelk, P. Trautner, H.G. Niessen, and R. E. Gerald II, J. Magn. Reson. 159, 207 –212 (2002).

• A new pulse sequence is introduced for compensation of acoustic ringing effects, which occur in rotating-frame images obtained with the rapid imaging pulse trains (RIPT).

• The new sequence (RIDE'n RIPT) combines features of ring down elimination (RIDE), the most common difference-spectroscopy sequence for acoustic-ringing compensation, with the advantages of RIPT for fast acquisition of magnetization profiles in B₁ field gradients.

• For even greater time effciency in many experiments, the two transients of RIDE'n RIPT are combined to a single transient in which data for the difference spectroscopy are collected sequentially.

• RIDE'n RIPT was used to record one-dimensional profiles of the proton magnetization in supercritical fluid samples of methane in carbon dioxide. The profiles showed substantial improvements over profiles obtained from standard RIPT.

• To withstand the high pressures required for the supercritical carbon dioxide mixtures, a toroid cavity autoclave (TCA) was used as the NMR resonator and pressure vessel. The well-defined, strong, and nonuniform B₁ field of the TCA was used to resolve distances along the radial dimension.

K. Woelk, December 10, 2002