Spin echo formation in the presence of stochastic dynamics

Abstract

Spin echo formation in magnetic field gradients in the presence of fast stochastic motion is studied for hyperpolarized He3 gas at different diffusivities. The fast translational motion leads to frequency shifts already during echo formation, which can be described analytically for a linear gradient. Despite complete signal loss at the position of the spin echo itself, considerable intensity can be preserved at an earlier time (2τ rather than 2τ, where τ is the pulse delay). Hence, the phenomenon is designated as a pseudo spin echo. © 2007 The American Physical Society.