Beta-ray Detection Of Nuclear Magnetic Nuclear Resonance And Nucleus Nuclear Moment Measurement

β-nuclear magnetic resonance (β-NMR) and β-nuclear quadrupole resonance (β-NQR) is a nuclear resonance technique using unstable β-emitting nuclei as a probe, the detection sensitivity of which is a magnitude of 9 orders higher than the conventional nuclear magnetic resonance and nuclear quadrupole resonance. The β-NMR and β-NQR technique has been an indispensable experimental method in nuclear physics, particle physics and condensed matter physics and materials science. The β-NMR and β-NQR technique has made great contributions to the nuclear structure studies of unstable nuclei, which observed and confirmed some new physical phenomena such as the halo structure of proton-rich nuclei, the effective charge reduction of neutronβ-rich nuclei, the energy level shift and the anomalous enhancement of nuclear spin. Most of unstable nuclei far from the stability line are β-radioactive nuclei. Therefore, β-NMR and β-NQR has played and will play an important role in studying nuclear structure of unstable nuclei.In order to conduct the β-NMR and β-NQR study, especially, the measurements of nuclear moments and the investigation of nuclear structure and properties of unstable nuclei by it, the β-NMR and β-NQR set-up has been established in China Institute of Atomic Energy for the first time in China. The key techniques for β-NMR and β-NQR are the production of polarized unstable β-emitting nuclei, the maintenance of the polarization of unstable nuclei before β-decay, the destruction or inversion of polarization by application of an rf field that satisfies the resonance condition, and the detection of the angular distribution asymmetry of emitted β-rays. The constructed β-NMR and β-NQR set-up is mainly composed of the strong magnetic field and target chamber system, the beam pulsing system, the rf and its control system, and β-detection and data acquisition system. The β-NMR and β-NQR set-up is fully controlled by a PC computer.The precise measurement of the magnetic moment for 12B(I=l+,T1/2=20.18ms) was performed with this β-NMR and β-NQR set up. The 12B(I=1+,T1/2=20.18ms) nuclei were produced through the 11B(d, p) 12B reaction. The half-life time of 12B andthe polarization of 12B recoil-implanted into the Cu catcher were determined to be 20.18 0.72ms and 11.4%?.6%, respectively. The β-NMR spectrum for 12B in Cu was measured with an externally applied magnetic field of H0=2.1700 kG at room temperature. From the measured NMR frequency the magnetic moment or g-factor for 12B(I=1+,T1/2=20.18ms) was deduced to be = 1.00095 nm or g =1.00095. The Kinght shift effect should be considered for the precise measurements of magnetic moment. No or inadequate Knight shift correction was made in the earlier measurements. In the present work the Knight shift was accurately measured by measuring the spin-lattice relaxation time and using the Korringa relation with an electron-electron interaction taken into account. After the Knight shift correction the obtained magnetic moment or g-factor is = 0.99993 0.00048 nm or g =0.99993 0.00048. The experiment and the result obtained also shows that the newly built β-NMR and β-NQR set up works properly and reliably.The unstable β-emitting nuclide 17F located near the proton drip line is a good candidate of proton halo for its last proton separation energy is 0.6 MeV. The high Coulomb and centrifugal barriers make it difficult for light proton-rich nuclei to possess halo structure. The halo structure in the ground state in 17F that has been investigated is still controversial. It is exclusively useful to study nuclear halo structure by measuring the quadrupole moment that is sensitive to proton radial distribution. The quadrupole moment of the 17F(I=5/2+,T1/2=64.49s) nucleus was determined by using the β-NMR and β-NQR technique. The 17F nuclei were producedthrough the 16O(d,n) 17F reaction. The β-NQR spectrum for 17F in MgF2 wasmeasured at room temperature under an external magnetic field of 4.0000kG. A 5-line resonant spectrum was observed. In the framework of th...