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Kumar, V.*; Chapman, R.*; Ollier, J.*; Orlandi, R.; Smith, J. F.*; Spohr, K.-M.*; Torres, D. A.*; Wady, P.*; 他10名*
Physical Review C, 110(4), p.044308_1 - 044308_18, 2024/10
被引用回数:1 パーセンタイル:0.00(Physics, Nuclear)Excited states of the molybdenum isotopes Mo were populated in two experiments which used fusion-fission and binary grazing reactions. In the first experiment, the GASP array of Ge detectors was used to detect
rays from fusion-fission products from the
S +
Yb reaction at 230 MeV. In the multinucleon transfer experiment, a 530-MeV beam of
Zr ions was incident on a thin
Sn target; projectile-like ejectiles were detected and identified using the PRISMA magnetic spectrometer and their associated
rays detected using the CLARA array of Clover detectors. Previously known bands were extended in all isotopes, and a new g
band was established in
Mo. The observed level schemes were compared with shell-model calculations, which reproduce the general features of the energy spectrum of excited states of
Mo,
Mo, and
Mo, although not in detail. For the h
negative-parity decay sequences of the three isotopes studied, evidence is presented for nuclear shape changes with increasing neutron number.
Kumar, V.*; Chapman, R.*; O'Donnell, D.*; Ollier, J.*; Orlandi, R.; Smith, J. F.*; Spohr, K.-M.*; Torres, D. A.*; 他13名*
Physical Review C, 108(4), p.044313_1 - 044313_19, 2023/10
被引用回数:1 パーセンタイル:26.66(Physics, Nuclear)The nuclear structure of neutron-rich niobium isotopes Nb were studied at the Legnaro National Laboratories using
-ray spectroscopy. The isotopes were produced in two different experiments, either using multi-nucleon transfer reactions of
Zr 530-MeV beam onto a
Sn target, or via fusion-fission of
S on
Yb. The level schemes of these isotopes were extended respectively up to excitation energies of 4545, 5409, and 3814 keV. The structure of the low-lying states in these isotopes was interpreted and discussed in the context of shell-model calculations. In particular, for the
Nb isotope (
=41,
=58), the results indicate the presence of shape-coexistence at low-energies, which was observed for the first time in this isotope.
Torres, D. A.*; Chapman, R.*; Kumar, V.*; Hadinia, B.*; Hodsdon, A.*; Labiche, M.*; Liang, X.*; O'Donnell, D.*; Ollier, J.*; Orlandi, R.; et al.
European Physical Journal A, 55(9), p.158_1 - 158_21, 2019/09
被引用回数:1 パーセンタイル:11.42(Physics, Nuclear)Excited states of the rubidium isotopes Rb were studied at the INFN Legnaro National Laboratory. Measurements of the
-ray of nuclei produced in binary reactions from the interaction of a beam of 530 MeV
Zr ions with a
Sn target were complemented by studies of the
-rays from nuclei produced in the interaction of a beam of 230 MeV
S ions with a thick
Yb target. The structure of the yrast states of
Rb is discussed within the context of spherical shell-model and cranked Nilsson-Strutinsky calculations.
Orlandi, R.; Pain, S. D.*; Ahn, S.*; Jungclaus, A.*; Schmitt, K. T.*; Bardayan, D. W.*; Catford, W. N.*; Chapman, R.*; Chipps, K. A.*; Cizewski, J. A.*; et al.
Physics Letters B, 785, p.615 - 620, 2018/10
被引用回数:9 パーセンタイル:56.46(Astronomy & Astrophysics)Low-lying neutron-hole states in Sn were populated via the
Sn(d,t) reaction at Oak Ridge National Laboratory. The triton angular distributions were compared to DWBA calculations and revealed spectroscopic factors compatible with a single-hole nature of the states populated. The data permit to determine the spin-orbit splitting of the strongly bound
and
neutron orbits below the shell gap, which was compared to the splitting of the weakly bound 3
and 2
orbits above the gap. The comparison revealed a smaller energy splitting of the 3
orbits. All splittings were reproduced using Woods-Saxon calculations, and the lower splitting of the 3
orbits was explained to arise from the large radial extent of the wavefunction and small value of the amplitude at the surface. This result is important to understand at a fundamental level the spin-orbit interaction, and its effects on neutron-rich nuclei.
西尾 勝久; Andreyev, A. N.*; Chapman, R.*; Derkx, X.*; Dllmann, C. E.*; Ghys, L.*; He
berger, F. P.*; 廣瀬 健太郎; 池添 博*; Khuyagbaatar, J.*; et al.
Physics Letters B, 748, p.89 - 94, 2015/09
被引用回数:60 パーセンタイル:95.00(Astronomy & Astrophysics)Mass distributions of fission fragments from the compound nuclei Hg and
Hg formed in fusion reactions
Ar+
Sm and
Ar+
Sm, respectively, were measured at initial excitation energies of
(
Hg)=,33
66 MeV and
(
Hg)=,48
71 MeV. In the fission of
Hg, the mass spectra were well reproduced by assuming only an asymmetric-mass division, with most probable light and heavy fragment masses
/
79
101. The mass asymmetry for
Hg agrees well with that obtained in the low-energy
/EC-delayed fission of
Tl, from our earlier ISOLDE(CERN) experiment. Fission of
Hg is found to proceed in a similar way, delivering the mass asymmetry of
/
83
107, throughout the measured excitation energy range. The persistence as a function of excitation energy of the mass-asymmetric fission for both proton-rich Hg isotopes gives strong evidence for the survival of microscopic effects up to effective excitation energies of compound nuclei as high as 40,MeV. This behavior is different from fission of actinide nuclei and heavier mercury isotope
Hg.
Orlandi, R.; Mcher, D.*; Raabe, R.*; Jungclaus, A.*; Pain, S. D.*; Bildstein, V.*; Chapman, R.*; De Angelis, G.*; Johansen, J. G.*; Van Duppen, P.*; et al.
Physics Letters B, 740, p.298 - 302, 2015/01
被引用回数:29 パーセンタイル:84.62(Astronomy & Astrophysics)Single-neutron states in Zn have been populated using the reaction
Zn(d,p) at REX-Isolde, CERN. The analysis reveals that the lowest excited states in
Zn lie at approximately 1 MeV, and involve neutron orbits above the N=50 shell gap. A 5/2
configuration was assigned to the 983-keV state. Comparison with large-scale shell model calculations supports a robust neutron N=50 shell closure for
Ni. These data constitute an important step towards the understanding the magicity of
Ni and the structure of nuclei in the region.
Chapman, I. T.*; Buttery, R. J.*; Coda, S.*; Gerhardt, S.*; Graves, J. P.*; Howell, D. F.*; 諫山 明彦; La Haye, R. J.*; Liu, Y.*; Maget, P.*; et al.
Nuclear Fusion, 50(10), p.102001_1 - 102001_7, 2010/10
被引用回数:56 パーセンタイル:87.21(Physics, Fluids & Plasmas)本論文では、ASDEX-U, DIII-D, HL-2A, JET, JT-60U, MAST, NSTX, TCV, Tore Supraにおいて鋸歯状振動と新古典テアリングモード(NTM)の発生について調べた結果について記述している。データベース解析の結果、鋸歯状振動がNTMを誘起したときのベータ値は鋸歯状振動の周期とともに低下することがわかった。また、装置間で鋸歯状振動を比較する場合、鋸歯状振動周期を抵抗性拡散時間で規格化し、プラズマ圧力として規格化ベータ値()を用いることがよいことがわかった。今回の結果をITERに外挿した場合、鋸歯状振動周期が10秒の場合は
でNTMが誘起されると予想されるのに対し、鋸歯状振動周期が100秒の場合は
でNTMが誘起されると予想されることがわかった。
Orlandi, R.; Mcher, D.*; Raabe, R.*; Jungclaus, A.*; Pain, S. D.*; Bildstein, V.*; Chapman, R.*; De Angelis, G.*; Johansen, J. G.*; Van Duppen, P.*; et al.
no journal, ,
Single-neutron states in the = 49 isotope
Zn were populated in the
Zn(d,p)
Zn transfer reaction at REX-ISOLDE, CERN. The combined detection of protons ejected in the reaction and of
rays emitted by
Zn permitted the identification of the lowest-lying 5/2
and 1/2
excited states. The analysis of proton angular distributions links these states to a significant amount of single-particle strength around 1 MeV, and specifically to the
d
and
s
neutron orbits, which lie above the
= 50 neutron shell gap. Comparison with large-scale-shell-model calculations supports a robust
= 50 shell-closure for
Ni. These data constitute a considerable step towards the understanding of the magicity of
Ni and of the structure of isotopes in the region.
Orlandi, R.; Pain, S. D.*; Bardayan, D. W.*; Gross, C. J.*; Smith, M. S.*; Jungclaus, A.*; Ahn, S.*; Jones, K. L.*; Pittman, S. T.*; Schmitt, K. T.*; et al.
no journal, ,
Knowledge of single-particle energies in the vicinity of exotic doubly-magic nuclei is of critical importance to understand evolution of nuclear structure. In the present work, the Sn(d,t)
Sn reaction (Q=-1.055 MeV) was studied in inverse kinematics at HRIBF of Oak Ridge National Laboratory. The
Sn ISOL beam was post-accelerated to an energy of 4.39 MeV/u using the ORNL HRIBF accelerator. The beam (average intensity of
1.2e4 pps) impinged on a
250
g/cm
deuterated polyethylene target, for approximately 4 days. Ejected tritons were detected using the Super ORRUBA array of segmented Si telescopes. Low-lying states in
Sn were populated in the experiment. Preliminary results will be shown.