Nicholas Stone

Abstract:

The nuclear spin-lattice relaxation of In-127 implanted into pure gadolinium metal has been measured using the method of integral attenuation of on-line nuclear orientation. The Korringa constant is determined to be C-K ((InGd)-In-127, B-pol = 0.5 T) = 0.133(18) sK. The result is compared with relaxation of In nuclei in Fe.

Abstract:

We report a programme of novel experiments involving direct proton emission and beta-delayed proton and neutron emission for exotic nuclei oriented at low temperatures. Full modelling of the quantum tunneling and angular distribution has been made for the first time for these processes. Their study has application in many fields of natural science. The study of barrier effects involving angular momentum and non-spherical deformation can be approached more directly via single-particle emission than via alpha decay, which suffers from complications relating to preformation of the alpha particle. Using the new formalism, predictions are presented for angular distributions of beta-delayed neutrons from oriented I-137 and of direct proton emission from oriented Tm-147.

Abstract:

New results on the applied field dependence of the NMR of Se-75 implanted in pure iron and oriented at millikelvin temperatures are reported. They yield the magnetic hyperfine field acting on Se nuclei present as dilute impurities in the iron matrix and the magnetic dipole moment of the 5/2(+) ground state of Se-75 with significantly improved precision. The results are B-hf(SeFe) = +67.9(10) T and \mu\(Se-75) = 0.683(10) mu (N). The improved value of the hyperfine field, with data from [2], gives the magnetic dipole moment of the 9/2(+) ground state of Se-73 as \mu\ = 0.892(13) mu (N).