T. Sumikama

Quadrupole moments of neutron-deficient 20,21Na

Abstract The electric-quadrupole coupling constant of the ground states of the proton drip line nucleus 20Na ( I π = 2 + , T 1 / 2 = 447.9 ms ) and the neutron-deficient nucleus 21Na ( I π = 3 / 2 + , T 1 / 2 = 22.49 s ) in a hexagonal ZnO single crystal were precisely measured to be | e q Q / h | = 690 ± 12 kHz and 939 ± 14 kHz , respectively, using the multi-frequency β-ray detecting nuclear magnetic resonance technique under presence of an electric-quadrupole interaction. An electric-quadrupole coupling constant of 27Na in the ZnO crystal was also measured to be | e q Q / h | = 48.4 ± 3.8 kHz . The electric-quadrupole moments were extracted as | Q ( Na 20 ) | = 10.3 ± 0.8 e fm 2 and | Q ( Na 21 ) | = 14.0 ± 1.1 e fm 2 , using the electric-coupling constant of 27Na and the known quadrupole moment of this nucleus as references. The present results are well explained by shell-model calculations in the full sd-shell model space.

A Possible Nuclear Spin Dewar. Hyperfine Interactions of Short-Lived β Emitter 8Li and 12B in TiO2

It was confirmed by detecting the β-NMR of 12B (Iπ=1+, T1/2=20.2 ms) in a TiO2 (rutile) crystal that the nuclear spin polarization of 12B was totally maintained in the crystal as produced through a nuclear reaction before implantation. Two locations, site 1 and site 2, were found with the relative populations 9 and 1, respectively, and the electric field gradients (EFGs) at those sites were obtained to be q(site 1)=+(37.1±0.5)1015 V/cm2, η(site 1)<0.03, q(site 2)=+(185±5)1015 V/cm2 and η(site 2)=0.62±0.02. We also found that about 30% of the initial polarization of 8Li (Iπ=2+, T1/2=838 ms) was maintained in the crystal. Since the polarizations of other β emitting nuclei, 12,16N, 13,19O, and 41Sc were also totally maintained in the crystal, the crystal can be a “Spin Dewar” in which many short-lived nuclides can be implanted with their polarizations totally maintained during their lifetimes for the studies not only on the electronic structure of impurities in it but also on the nuclear properties.

Knight shifts for short-lived beta emitters in Pt

The Knight shifts K for short-lived β emitters 12N and 27Si implanted in Pt have been measured by means of β-NMR technique. The results were K(12N in Pt)= +(5.8 ± 2.1)× 10-4 and K(27Si in Pt)= +(1.4 ± 0.8)× 10-3. The spin–lattice relaxation time T1 was measured for 12N in Pt. The result was T1(12N in Pt, T=300 K)= 66 ± 8 ms, thus, T1T= 20 ± 2 Ks. The present Knight shifts are in good agreement with the KKR band structure calculation with local lattice relaxation determined theoretically.

Test of the conserved vector current hypothesis by a β -ray angular distribution measurement in the mass-8 system

The

Precise magnetic moment of short-lived beta emitter 35Ar

ensuremath{beta}

G-parity irregular current in the β decays of the mass A = 12 system - with the refined empirical value of the weak magnetism -

-ray angular correlations for the spin alignments of

Nuclear Spin Alignment of 12,13B Produced in Heavy Ion Collisions

^{8}mathrm{Li}

New limit of the G-parity irregular weak nucleon current detected in β decays of spin aligned 12B and 12N

and

Spin polarization of beta-emitting fragments in high energy heavy ions on Be collisions

^{8}mathrm{B}

Nuclear polarization of short-lived Na isotopes maintained in single crystals for β-NMR spectroscopy

have been observed in order to test the conserved vector current (CVC) hypothesis. The alignment correlation terms were combined with the known