Structure of 55Sc and development of the N=34 subshell closure

The low-lying structure of $^{55}$Sc has been investigated using in-beam $\gamma$-ray spectroscopy with the $^{9}$Be($^{56}$Ti,$^{55}$Sc+$\gamma$)$X$ one-proton removal and $^{9}$Be($^{55}$Sc,$^{55}$Sc+$\gamma$)$X$ inelastic-scattering reactions at the RIKEN Radioactive Isotope Beam Factory. Transitions with energies of 572(4), 695(5), 1539(10), 1730(20), 1854(27), 2091(19), 2452(26), and 3241(39) keV are reported, and a level scheme has been constructed using $\gamma\gamma$ coincidence relationships and $\gamma$-ray relative intensities. The results are compared to large-scale shell-model calculations in the $sd$-$pf$ model space, which account for positive-parity states from proton-hole cross-shell excitations, and to it ab initio shell-model calculations from the in-medium similarity renormalization group that includes three-nucleon forces explicitly. The results of proton-removal reaction theory with the eikonal model approach were adopted to aid identification of positive-parity states in the level scheme; experimental counterparts of theoretical $1/2^{+}_{1}$ and $3/2^{+}_{1}$ states are suggested from measured decay patterns. The energy of the first $3/2^{-}$ state, which is sensitive to the neutron shell gap at the Fermi surface, was determined. The result indicates a rapid weakening of the $N=34$ subshell closure in $pf$-shell nuclei at $Z>20$, even when only a single proton occupies the $\pi f_{7/2}$ orbital

Spectroscopy of 98Ru

The nucleus 98 Ru has been investigated by means of γ - γ coincidence, γ - γ angular correlation and K-internal conversion coefficient measurements. The results have led to spin-parity assignment to several levels and to the determination of E 2/ M 1 mixing ratios for the most intense transitions

238U(n, γ) reaction cross section measurement with C 6D6 detectors at the n-TOF CERN facility

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe radiative capture cross section of 238U is very important for the developing of new reactor technologies and the safety of existing ones. Here the preliminary results of the 238U(n,γ) cross section measurement performed at n-TOF with C6D6 scintillation detectors are presented, paying particular attention to data reduction and background subtraction.Peer reviewe

The nucleosynthesis of heavy elements in Stars : The key isotope 25Mg

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedWe have measured the radiative neutron-capture cross section and the total neutron-induced cross section of one of the most important isotopes for the s process, the 25Mg. The measurements have been carried out at the neutron time-of-flight facilities n-TOF at CERN (Switzerland) and GELINA installed at the EC-JRC-IRMM (Belgium). The cross sections as a function of neutron energy have been measured up to approximately 300 keV, covering the energy region of interest to the s process. The data analysis is ongoing and preliminary results show the potential relevance for the s process.Peer reviewe

Vibrational and rotational sequences in 101 Mo and 103,4 Ru studied via multinucleon transfer reactions

The near yrast states of 101 Mo and 103,104 Ru have been studied following their population via heavy ion multinucleon transfer reactions between a 136 Xe beam and a thin, self supporting 100 Mo target. The ground state sequence in 104 Ru can be understood as demonstrating a simple evolution from a quasi vibrational structure at lower spins to statically deformed, quasi rotational excitation involving the population of a pair of low Omega h11 2 neutron orbitals. The effect of the decoupled h11 2 orbital on this vibration to rotational evolution is demonstrated by an extension of the E GOS prescription to include odd A nuclei. The experimental results are also compared with self consistent Total Routhian Surface calculations which also highlight the polarising role of the highly aligned neutron h11 2 orbital in these nucle

Transfer Reaction Studies with Spectrometers

The revival of transfer reaction studies benefited from the construction of the new generation large solid angle spectrometers, coupled to large gamma arrays. The recent results of gamma-particle coincident measurements in Ca-40+Zr-96 and Ar-40+Pb-208 reactions demonstrate a strong interplay between single-particle and collective degrees of freedom that is pertinent to the reaction dynamics. The development of collectivity has been followed in odd Ar isotopes populated in the Ar-40+Pb-208 reaction through the excitation of the 11/2(-) states, understood as the coupling of single particle degrees of freedom to nuclear vibration quanta. Pair transfer modes is another important degree of freedom which is presently being studied with Prisma in inverse kinematics at energies far below the Coulomb barrier. First results from the Zr-96+Ca-40 reaction elucidate the role played by nucleon-nucleon correlation