Spin–spin relaxation

Spin-spin relaxation refers to a process in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) that describes the loss of coherence among spins in a magnetic field over time. This phenomenon is often denoted by the time constant \( T_2 \). In a simplified explanation: 1. **Nuclear Spins and Coherence**: In an external magnetic field, nuclei with non-zero spin (like protons in hydrogen) tend to align either parallel or anti-parallel to the field.