Narrow Results

Typical elements in PET bottled mineral water and in running water of public waterworks near by our cyclotron center was investigated by PIXE. We can detect typical elements in water sample using only a pipette. After water sample was preserved in a brown-glass vessel or a clear-glass vessel, Ba and Ti consisting in the vessels were detected in water samples. Concentration of typical elements in running water is found to be equal to that in PET bottled mineral water.

Photonuclear reactions have great importance in understanding the structure of the nuclei. These reactions, performed using the gamma rays obtained by way of bremsstrahlung, are a standard nuclear physics experiment. In this study, a non-enriched barium sample was activated for the first time by using a clinical linear accelerator (cLINACs). The spectrum of barium radioisotopes was obtained by using a gamma spectrometry with a high purity germanium (HPGe) detector. The obtained spectroscopic data were analyzed and energy levels and half-life values together with their uncertainties were obtained. Some energy levels and half-lives of ${}^{129}$Ba were determined with more precision than those of literature values.

Magic wavelengths for laser trapping of barium atoms in the optical lattices are investigated while considering the optical clock transition at 877 nm between the 6s²¹S₀ state and 6s5d ¹D₂ state. Theoretical calculation shows that there are several magic wavelengths with the linearly polarized trapping laser. The trap depths of the optical lattice and the slope of light shift difference with different magic wavelengths are also discussed and analyzed. Some of these magic wavelengths are selected and recommended for the optical lattice trapping laser.

The experimental measurements of the isotope shifts (ISs) for the ¹S₀–³P₁ spin-forbidden transition at 791 nm in neutral barium have been carried out with a thermal barium atom beam. The hyperfine structure (HFS) constants a and b of the odd isotopes ${}^{137}$Ba and ${}^{135}$Ba for this transition have been extracted from the experimental results: a(${}^{137}$Ba) = 1149.9(1.0) MHz, b(${}^{137}$Ba)= −41.6(0.5) MHz, a(${}^{135}$Ba) = 1028.0(1.0) MHz, b(${}^{135}$Ba) = −27.5(0.5) MHz. The measured IS results with the reference isotope ${}^{138}$Ba are 183.7(1.0) MHz (${}^{137}$Ba–${}^{138}$Ba), 108.5(0.3) MHz (${}^{136}$Ba–${}^{138}$Ba) and 218.9(1.0) MHz (${}^{135}$Ba–${}^{138}$Ba). Our IS measurements are in good agreement with the previous experiments. The field shift (FS) factor $F_k$ and the mass shift (MS) coefficient $\mathrm{\Delta }{K}^{\mathrm{\text{MS}}}$ for this spin-forbidden transition have be determined experimentally as −3.19(4) GHz ⋅ fm${}^{-2}$ and −242(20) GHz ⋅ amu, respectively. The results provided herein could be used for further checks theoretically and experimentally, and could also contribute to the study on the nuclear structure of the barium isotopic nuclei.

In this paper, we study the adsorption of Ba on the Ni(110) surface at room temperature. The investigation takes place mainly by soft X-ray photoelectron spectroscopy measurements. At low coverage (<0.5 ML), the Ba adatoms are in a partially ionic state, whereas at higher coverage, the barium overlayer becomes metallic. The nonmetal to metal transition is characterized by a new Ba 4d doublet appearing at higher binding energy. This more bound Ba 4d core state is attributed to initial state changes of the electrostatic potential at the atomic core region, due to changes in the hybridization of the Ba atoms from Ba 5d with Ni 3d, to Ba 5d, 6s and 6p states in the metallic phase. The latter states are more spatially extended than the Ba 5d ones, overlapping with the Ni 3d orbitals in the nonmetal and therefore lead to a reduced potential at the core electrons. A strong effect on the Ba 4d binding energy shifts, due to the surface dipole induced by the adsorbate itself, was observed.

Fine particles of barium hexaferrite were synthesized by chemical co-precipitation method in the nitrate (barium and iron nitrates) and acetate-nitrate (barium acetate + iron nitrate) systems. Thermal properties, phase composition and morphology of hexaferrite powders obtained from two chemical systems were studied. Simultaneous DTA/TG and XRD indicated that the formation of the barium hexaferrite in the acetate-nitrate system occurs at a relatively low temperature. The SEM investigations indicated that the mean particle size of barium hexaferrite increases by increasing the calcination temperature. In the acetate-nitrate system the Fe/Ba molar ratio of 12 (stoichiometric ratio) is favourable. In the nitrate system excess Ba²⁺ is needed.

The octupole strength present in the neutron-rich, radiocative nucleus ¹⁴⁶Ba has been experimentally determined for the first time using Coulomb excitation. To achieve this, A=146 fission fragments from CARIBU were post-accelerated by the Argonne Tandem Linac Accelerator System (ATLAS) and impinged on a thin ²⁰⁸Pb target. Using the GRETINA γ-ray spectrometer and the CHICO2 heavy-ion counter, the reduced transition probability B(E3; 3⁻→0⁺) was determined as $48\left(\begin{array}{l}+21\\ -29\end{array}\right)$ W.u. The new result provides further experimental evidence for the presence of a region of octupole deformation surrounding the neutron-rich barium isotopes.

Gamma rays emitted by fission fragments of ²⁵²Cf and measured using the Gammasphere array continue to give insight into neutron rich nuclei. Using our high statistics data, we have reexamined high-spin states and linking transitions associated with octupole correlations in ¹⁴⁴Ba and ¹⁴⁸Ce. In an even-A system, it is possible that rotational band structures are explainable by simplex quantum numbers, s = +1 and s = -1. In ¹⁴⁴Ba and 148Ce we have deduced spin values from angular correlations and assigned parities from mixing ratios for s = -1 characterized states. These are the first examples of both simplex bands in even-even nuclei. Extensions to higher spins of bands in ¹⁴⁴Ba and in ¹⁴⁸Ce are also reported. In addition to collective model analysis of energy displacement and rotational frequency, the intrinsic dipole moment via B(E2)/B(E1) ratios are also analyzed.