Development of a Nuclear Spin Dewar: Hyperfine Interactions of the Short-Lived Emitter 12B in TiO2

Abstract

The β-NMR detection of 12B ( Iπ= 1+, T1/2 = 20.2 msec) implanted in a TiO2 (rutile) single crystal following a nuclear reaction showed that its spin polarization produced in the reaction is totally maintained during its lifetime. Two implantation sites with relative populations 9:1 were identified. The electric field gradients (EFGs) were determined to be q = +(37.1 0.5) 1015 V/cm2 with η< 0.03 and q = +(185 5) 1015 V/cm2 with η= 0.62 0.02 for the major (90%) and minor (10%) sites, respectively. The EFGs were compared with the theoretical values given by the band-structure calculation in the framework of the KKR method. TiO2 crystals with proper treatment can be a good “Spin Dewar” in which any short-lived nuclei can be implanted, and their spin polarizations as produced in nuclear reactions can be maintained during their lifetime