[en] Decay of mass-separated samples of the nuclide ⁷³Br have been investigated by means of an on-line isotope separator in the Tandem Accelerator Laboratory of Kyushu University. Twenty eight γ-rays were assigned to the decay of ⁷³Br. The half-life was measured to be 3.4±0.2 min. The decay scheme of ⁷³Br was constructed on the basis of γ-ray energies, intensities of γ-rays and conversion electrons, and relations of γγ-, βγ- and γ(ce)-coincidences. Spins and parities of the ten levels of ⁷³Se were assigned or limited according to log ft values, conversion coefficients and branching ratios of the transitions. Systematical trends in the level schemes of N=39 isotones ⁶⁹Zn, ⁷¹Ge, ⁷³Se, ⁷⁵Kr and ⁷⁷Sr are discussed. (orig.)

[en] Published in summary form only

[en] The reactions ⁵⁸Ni(³²S, 3p)⁸⁷Nb were used to populate excited states in ⁸⁷Nb. The deexcitation of these states was studied by in-beam γ-ray spectroscopy. Measurements of (p, α)-γ coincidence, p-γ γ coincidence and γ-ray angular distribution were performed. The level scheme of ⁸⁷Nb up to 6MeV in excitation energy was deduced. Spin and parity of ground state of ⁸⁷Nb were decided from the β-decay study of ⁸⁷Mo. The new decay scheme of ⁸⁷Mo was also deduced. (author)

[en] Published in summary form only

[en] The neutron deficient isotope ⁷⁹Y has been firstly identified and the decay properties were studied from β-decay measurements in the reaction of ⁵⁴Fe(²⁸Si, p 2n) at 92 MeV. Three γ rays of 152.5, 177.4, and 1106 keV were observed concerning the β decay. The half life and Q_EC value were determined to be 14.9±0.6 s and 7.12±0.45 MeV, respectively. The decay scheme including spin-parity is discussed, and 5/2⁺ assignment for the ground state is proposed. (orig.)

[en] High-spin states in ⁸³Zr have been studied via the ⁵⁸Ni(²⁸Si,2pn)⁸³Zr reaction using in-beam gamma-ray spectroscopy techniques. Measurements of multiple (charged-particle)γ-coincidence, nγγ-coincidence, gamma-ray excitation function and gamma-ray angular distribution were performed. These experimental results established a positive-parity band based on the g_9/2 neutron shell and two negative-partity bands built on the 1/2^- and 5/2^- states. The existence of the two low-lying isomeric states with the half-lives of 1.8 → 0.1 and 0.50 → 0.25 μs was also revealed. It was found that each band exhibits a rotational-lie character and the structures are similar to those of neighboring N = 43 isotones, whereas change of neutron number leads to abrupt change at N = 43 ≅ 45 with regard to the level structure of odd-Zr isotopes. (orig.)

[en] The magnetic hyperfine splitting frequencies of ⁹⁰NbNi and ^93mMoNi in an external magnetic field of 0.2 T have been determined by the NMR-ON method to be 18.52(7) and 23.73(10) MHz, respectively. With the assumption of Knight shift factor K = 0 and with the known g-factors, the hyperfine fields of ⁹⁰NbNi and ^93mMoNi were deduced as B_HF(⁹⁰NbNi) = -4.118(16) T and B_HF(^93mMoNi) = -3.491(33) T. The rather long spin-lattice relaxation time of 32(5) min was observed for ⁹⁰NbNi at an external magnetic field of 0.2 T and 8 mK. (orig.)

[en] A charged particle multiplicity filter was developed to investigate excited states in neutron-deficient nuclei far from the β-stability line. This system enabled the determination of the atomic numbers of γ-emitting nuclei for many of the γ-rays produced by the compound nuclear reactions. Details and performance of the system are described and an application is demonstrated for the ⁶⁰Ni+²⁸Si reaction. (orig.)

[en] The magnetic hyperfine splitting frequencies of ¹²³INi, ¹²⁴INi and ¹³¹INi in a zero external magnetic field have been determined by the NMR-ON method as 258.9(1), 165.9(1) and 179.5(2) MHz, respectively. With the known values of the magnetic moments, the magnetic hyperfine fields have been deduced: B_HF(¹²³INi)=30.17(5) T, B_HF(¹²⁴INi)=30.14(9) T, B_HF(¹³¹INi)=30.06(4) T; the weighted average is B_HF(INi)=30.11(4) T. The small difference of the B_HF(¹³¹INi) with those of ¹²³INi and ¹²⁴INi is discussed comparing with results of the hyperfine splitting frequency of iodine in iron host. (orig.)

[en] The level structure of ⁸⁷Nb has been studied through β-decay of ⁸⁷Mo activity produced by the ⁵⁸Ni(³²S, 2pn) reaction and through in-beam γ-ray measurements in the ⁵⁸Ni(³²S, 3pγ)⁸⁷Nb reaction. In the β-decay study, the decay scheme of ⁸⁷Mo is constructed firstly from γ-ray energies, intensities of γ-rays and conversion electrons, and γγ-, βγ- and γ(ce)-coincidence relations. Spins and parities of the low-lying states of ⁸⁷Nb and ⁸⁷Zr were also investigated. In the in-beam study, intensities, coincidence relations and angular distributions of γ-rays were measured in coincidence with charged particles evaporated from the compound nuclei. Then high-spin states of J^π ≤ (33/2⁺) in ⁸⁷Nb were established in this study. Systematic behavior in the level structures of N=46 isotones, and the comparison between those of ⁸⁵Y and ⁸⁷Nb, are discussed. (orig.)