Development of the pulse NMR method utilizing the short-lived β-emitter 12 B

Measurements of the spin-spin relaxation time T 2 of the short-lived \(\upbeta \)-emitter \(^{12}B (I^{\uppi }\) = 1 + , T 1/2 = 20 ms) in Si have been performed. By applying the spin echo method to \(\upbeta \)-NMR measurements, the intrinsic T 2 for 12B in Si was successfully determined with the effect of the static magnetic field inhomogeneity removed. The temperature dependence of T 2 for 12B in Si shows that T 2 becomes longer with increasing temperature, which seems to reflect the effect of motional narrowing.