The nucleus Ne-29 is situated at the border of the island of inversion. Despite significant efforts, no bound low-lying intruder f(7/2) state, which would place Ne-29 firmly inside the island of ...inversion, has yet been observed. Here, the first investigation of unbound states of Ne-29 is reported. The states were populated in Ne-30(p, pn) and Na-30(p, 2p) reactions at a beam energy of around 230 MeV/nucleon, and analyzed in terms of their resonance properties, partial cross sections, and momentum distributions. The momentum distributions are compared to calculations using the eikonal, direct reaction model, allowing assignments for the observed states. The lowest lying resonance at an excitation energy of 1.48(4) MeV shows clear signs of a significant l = 3 component, giving first evidence for f(7/2) single particle strength in Ne-29. The excitation energies and strengths of the observed states are compared to shell-model calculations using the SDPF-U-MIX interaction.
Calibration of large neutron detection arrays using cosmic rays Zhu, K.; Tsang, M. B.; Dell’Aquila, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2020, Letnik:
967
Journal Article
Recenzirano
Odprti dostop
Cosmic muons are used to calibrate the position, light output and the relative timing offset of the Large Area Neutron Array (LANA). Each 2 × 2 m2 LANA wall consists of twenty-five horizontal neutron ...detection bars. Each bar is 2 m long with a cross-section of 6.35 × 7.62 cm2 Pyrex container filled with NE-213 organic scintillation liquid. The average position and time resolution of a bar is found to be about 8 cm and 500 ps FWHM, respectively. Furthermore, our method provides an accurate, fast and convenient calibration of LANA that can be applied to general scintillation arrays without the use of radioactive sources or beams.
We have studied spin observables in the three-body break-up reaction in deuteron–deuteron scattering in the phase-space regime that corresponds to the quasi-free deuteron–proton scattering process ...with the neutron as spectator. The data are compared to measurements of the elastic deuteron–proton scattering process and state-of-the-art Faddeev calculations. The results for iT11 and T22 for the quasi-free scattering data agree very well with previously published elastic-scattering data. A significant discrepancy is found for T20, which could point to a break-down of the quasi-free assumption.
States in the N=35 and 37 isotopes 55,57Ca have been populated by direct proton-induced nucleon removal reactions from 56,58Sc and 56Ca beams at the RIBF. In addition, the (p,2p) quasi-free ...single-proton removal reaction from 56Ca was studied. Excited states in 55K, 55Ca, and 57Ca were established for the first time via in-beam γ-ray spectroscopy. Results for the proton and neutron removal reactions from 56Ca to states in 55K and 55Ca for the level energies, excited state lifetimes, and exclusive cross sections agree well with state-of-the-art theoretical calculations using different approaches. The observation of a short-lived state in 57Ca suggests a transition in the calcium isotopic chain from single-particle dominated states at N=35 to collective excitations at N=37.
.
High-quality vector analyzing power data for the
1
H(
d
,pp)n breakup reaction and elastic scattering at 100MeV beam energy have been measured in a large part of the phase space for these ...processes. The results are compared to theoretical predictions obtained using the charge-dependent Bonn potential alone or combined with the three-nucleon force TM99 as well as to the results of calculations in the coupled-channel approach, with or without the inclusion of the Coulomb interaction. In the studied observables, effects of the 3NF and the Coulomb force are almost absent. The pairwise NN interactions alone are sufficient to describe the experimental results.
A phoswich array consisting of 60 elements has been built and used in pionic-fusion experiments at the Kernfysisch Versneller Instituut (KVI). The array is used in conjunction with a magnetic ...spectrometer and a time-of-flight system to measure the fragments produced in
3He+
4He and
4He+
6Li reactions at beam energies of 85.3 and 59.1
A
MeV, respectively. The particle identification for
Z
≤
5
has been performed by means of time-of-flight and pulse-shape analysis techniques. A momentum resolution of
∼
1
%
was achieved. The dependence of the integrated light output on ion energy, momentum, and mass has been studied. The detector performance, light response, ion identification, momentum and time calibration, and acceptance of the Heavy-Ion detector array are presented and discussed.
Differential cross sections and vector analyzing powers for the p + d arrow right p + d reaction have been measured using a new experimental setup (BINA) at KVI. The data are compared with published ...results and are found to be significantly different. PUBLICATION ABSTRACT
The role of pions in the nuclear interaction has been studied in pionic fusion experiments using the AGOR accelerator facility at KVI. Pionic fusion is a highly coherent process in which two nuclei ...fuse to a united nucleus and the available centre-of-mass (C.M.) energy is emitted through the pion channel. The examined reactions were 4He(3He, π0)7Be and 6Li(4He, π0)10B⁎ and both reactions were performed at C.M. energies about 10 MeV above the coherent pion production threshold. Here, the experimental results for the 6Li(4He, π0)10B⁎ reaction will be presented and discussed. In order to provide sensitivity to the full dynamics and relevant processes involved in the pionic fusion reaction, almost the full angular distribution of neutral pions has been determined. In a phenomenological analysis, the contributions of Legendre polynomials to reproduce the behaviour of the angular distribution have been studied. The results of this analysis confirm the importance of the clustering correlations for the 6Li(4He, π0)10B⁎ reaction. The mass dependence of the pionic fusion reaction is in agreement with the results of the existing models extrapolated to this reaction.
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