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Accueil > Recherche > Structure Nucléaire (ou groupe "Exotique")

Publications

(more recent)

[in2p3-01394089] Experimental study of high-lying states in $^{28}$Mg using the resonant elastic scattering of α particles

9 novembre 2016

The excitation function of Mg28 above the α-decay threshold has been measured for the first time using the resonant scattering of α particles with the technique of a thick target in inverse kinematics. Thirteen new states are reported between Ex=15.5 and Ex=20.5 MeV, and suggestions for (...)

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[in2p3-01368398] A New Neutron Time-of-Flight Array for β-Decay Studies

20 septembre 2016

A new time-of-flight array for β-delayed neutron spectroscopy (En 5 MeV) is being developed with the aim of improved performance compared to existing arrays. We report on the status of this development, in particular the study of the n-γ discrimination quality with digital electronics, a (...)

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[in2p3-01367797] Interaction cross section study of the two-neutron halo nucleus $^{22}$C

17 septembre 2016

The interaction cross sections (σI) of the very neutron-rich carbon isotopes 19C, 20C and 22C have been measured on a carbon target at 307, 280, and 235MeV/nucleon, respectively. A σIof 1.280 ±0.023bwas obtained for 22C, significantly larger than for 19,20C, supporting the halo character of 22C. A (...)

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[in2p3-01294414] Study of the near-barrier scattering of $^{8}$He on $^{208}$Pb

29 juin 2016

The structure and dynamics of 8He have been studied through the collision process with a 208Pb target at energies of 22 and 16 MeV, above and below the Coulomb barrier, respectively. The energy and angular distributions of the elastically scattered 8He and the 6;4He fragments were measured. In (...)

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[in2p3-01198941] Invariant Mass Spectroscopy of $^{17}$C via One-neutron Knockout Reaction of $^{18}$C

29 juin 2016

Unbound states in 17C were investigated via one-neutron knockout of 18C. The experiment was performed using SAMURAI spectrometer in RIBF at RIKEN. By invariant mass spectroscopy, three resonances were measured at excitation energies of 3.03(12), 2.74(3), and 4.03(6) MeV as preliminary results. (...)

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[in2p3-01198949] Study of $^{19}$C by One-Neutron Knockout from $^{20}$C

29 juin 2016

The present work aims at exploring neutron-unbound states of 19C via the one-neutron knockout reaction. The invariant mass measurement in inverse kinematics was carried out with a carbon target and a 20C secondary beam at 290 MeV/nucleon. The preliminary relative energy spectrum and the parallel (...)

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[in2p3-01326382] Shell evolution approaching the N=20 island of inversion: Structure of 26Na

4 juin 2016

The levels in 26Na with single particle character have been observed for the first time using the d(25Na, pγ ) reaction at 5 MeV/nucleon. The measured excitation energies and the deduced spectroscopic factors are in good overall agreement with (0+1)ħω shell model calculations performed in a (...)

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[in2p3-01306171] $\alpha$ clustering in Ti isotopes: $^{40,44,48}$Ca + $\alpha$ resonant scattering

23 avril 2016

Measurements were made of the 4He(40,44,48Ca,α) resonant scattering reactions at 180° and up to Ec.m. ~ 11.5MeV, using the Thick Target Inverse Kinematics technique. These measurements are discussed, with a focus on assessing their usefulness for investigating α-clustering in medium mass (...)

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[in2p3-01297888] Study of $^{19}$C by One-Neutron Knockout

23 avril 2016

The spectroscopic structure of 19C, a prominent one-neutron halo nucleus, has been studied with a 20C secondary beam at 290 MeV/nucleon and a carbon target. Neutron-unbound states populated by the one-neutron knockout reaction were investigated by means of the invariant mass method. The (...)

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[in2p3-01301897] Spectroscopy of $^{17}$C via one-neutron knockout reaction

19 avril 2016

A spectroscopic study of 17C was performed via the one-neutron knockout reaction of 18C on a carbon target at RIKEN-RIBF. Three unbound states at excitation energies of 2.66(2), 3.16(5), and 3.97(3) MeV (preliminary) were observed. The energies are compared with shell-model calculations and (...)

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[in2p3-01285922] Nucleus $^{26}$O: A Barely Unbound System beyond the Drip Line

11 mars 2016

The unbound nucleus 26O has been investigated using invariant-mass spectroscopy following one-proton removal reaction from a 27F beam at 201 MeV/nucleon. The decay products, 24O and two neutrons, were detected in coincidence using the newly commissioned SAMURAI spectrometer at the RIKEN (...)

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[in2p3-01278370] Second 0+ state of unbound $^{12}$O: Scaling of mirror asymmetry

26 février 2016

The unbound O12 nucleus was studied via the two-neutron transfer (p,t) reaction in inverse kinematics using a radioactive O14 beam at 51 MeV/u. Excitation energy spectra and differential cross sections were deduced by the missing mass method using MUST2 telescopes. We achieved much higher (...)

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[in2p3-01278370] Second 0+ state of unbound $^{12}$O: Scaling of mirror asymmetry

26 février 2016

The unbound O12 nucleus was studied via the two-neutron transfer (p,t) reaction in inverse kinematics using a radioactive O14 beam at 51 MeV/u. Excitation energy spectra and differential cross sections were deduced by the missing mass method using MUST2 telescopes. We achieved much higher (...)

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[in2p3-01244201] Structure of $^{26}$Na via a Novel Technique Using ($d,p\gamma $) with a Radioactive $^{25}$Na Beam

16 décembre 2015

States in 26Na were populated in the (d, pγ) reaction, induced by bombarding deuterium target nuclei with an intense reaccelerated beam of 25Na ions from the ISAC2 accelerator at TRIUMF. Gamma-rays were recorded in coincidence with protons and used to extract differential cross sections for 21 (...)

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[in2p3-01222563] Observation of isoscalar multipole strengths in exotic doubly-magic $^{56}$Ni in inelastic α scattering in inverse kinematics

31 octobre 2015

The Isoscalar Giant Monopole Resonance (ISGMR) and the Isoscalar Giant Dipole Resonance (ISGDR) compression modes have been studied in the doubly-magic unstable nucleus $^56$Ni. They were measured by inelastic α-particle scattering in inverse kinematics at 50 MeV/u with the MAYA active target at (...)

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[in2p3-01213933] New findings on structure and production of $^{10}He$ from $^{11}Li$ with the (d,$^{3}He$) reaction

10 octobre 2015

We present the first missing mass spectrum of the unbound nucleus He10, measured at RIKEN using the Li11(d,He3) reaction at 50A MeV. He10 is believed to be a three-body He8+n+n resonance beyond the limit of nuclear binding. Our observation of a new decay branch, 6He+4n, and of a puzzling (...)

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[in2p3-01198919] Missing mass spectroscopy of $^{8}$He and $^{10}$He by (d,$^{3}$He) reaction

15 septembre 2015

We present the first missing mass spectrum of the unbound system 10He obtained from one nucleon transfer $^11$Li(d,$^3$He) reaction at 50 A MeV. We found rather large yields for the $^6$He + 4n decay channel especially for higher excitation energy, which suggest the importance of the $^6$He + 4n (...)

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[in2p3-01196659] Measurement of the Isoscalar Monopole Response in the Neutron-Rich Nucleus $^{68}$Ni using the active target MAYA

11 septembre 2015

We report the measurement of the isoscalar monopole strength in the unstable nucleus $^68$Ni using inelastic alpha scattering at 50AMeV in inverse kinematics. This experiment has been performed at GANIL with LISE spectrometer using a dedicated detector: the active target MAYA. A part of the (...)

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[in2p3-01179429] Isoscalar response of $^{68}$Ni to $\alpha$-particle and deuteron probes

23 juillet 2015

Isoscalar giant resonances have been measured in the unstable Ni68 nucleus using inelastic alpha and deuteron scattering at 50A MeV in inverse kinematics with the active target MAYA at GANIL. Using alpha scattering, the extracted isoscalar giant monopole resonance (ISGMR) centroid was (...)

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[in2p3-01177619] The Billotron: a way to experimentally apprehend the subatomic world

18 juillet 2015

The Billotron is a device designed and built by the LPC Caen to illustrate the methods with which physicists are able to study the basic structure of matter, in particular the nucleus of the atom.

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[in2p3-01163177] Tracking rare-isotope beams with microchannel plates

17 juillet 2015

A system of two microchannel-plate detectors has been successfully implemented for tracking projectile-fragmentation beams. The detectors provide interaction positions, angles, and arrival times of ions at the reaction target. The current design is an adaptation of an assembly used for (...)

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[in2p3-01130200] 12C+p resonant elastic scattering in the Maya active target

11 juillet 2015

In a proof-of-principle measurement, the Maya active target detector was employed for a 12C(p, p) resonant elastic scattering experiment in inverse kinematics. The excitation energy region from 0 to 3MeV above the proton breakup threshold in 13N was investigated in a single measurement. By (...)

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[in2p3-01133721] Exploring the structure of the most neutron-rich Boron and Carbon isotopes

11 juillet 2015

The most neutron-rich isotopes of boron and carbon are of considerable interest in terms of their few-body character - most notably through the possible formation of twoneutron haloes in the Borromean nuclei 19B and 22C. Here a series of recent investigations are briefly reviewed, including (...)

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[in2p3-01117025] Spectroscopic study of the exotic nucleus 25P

11 juillet 2015

Motivated by the importance of 25P for the two-proton decay of 26S and for searches of the mirror analog of the island of inversion near N = 16, we present the first predictions for the spectroscopy of the exotic isotope 25P obtained in the shell model, a potential model, and a (...)

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[in2p3-00823229] Breakup Reactions of Drip-Line Nuclei Near N = 20, 28

10 juillet 2015

The one-neutron removal cross section from 29Ne, 33,35,37Mg, and 39,41Si on a Pb target have been measured at around 240 MeV/nucleon at the RIBF (RI-Beam Factory) at RIKEN. This main goal of the experiment was to extract the inclusive Coulomb breakup cross sections in order to probe possible (...)

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[in2p3-00943130] Two-neutron transfer reaction mechanisms in 12C(6He,4He)14C using a realistic three-body 6He model

10 juillet 2015

The reaction mechanisms of the two-neutron transfer reaction 12C(6He,4He) have been studied at Elab=30 MeV at the TRIUMF ISAC-II facility using the Silicon Highly-segmented Array for Reactions and Coulex (SHARC) charged-particle detector array. Optical potential parameters have been extracted (...)

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[in2p3-00804461] Study of neutron rich nucleus 25F via single-step fragmentation

10 juillet 2015

The structure of nucleus 25F was studied by use of in-beam -ray spectroscopy of the fragmentation of a 36S beam. The emitted rays were detected by BaF2 detectors. In the -ray spectrum obtained a wide bump between 3 and 4.5 MeV energy was observed corresponding to a set of rays, including their (...)

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[in2p3-00925064] Experimental study of the two-body spin-orbit force

10 juillet 2015

Energies and spectroscopic factors of the first $7/2^-$, $3/2^-$, $1/2^-$ and $5/2^-$ states in the $^35$Si$_21$ nucleus were determined by means of the (d,p) transfer reaction in inverse kinematics at GANIL using the MUST2 and EXOGAM detectors. By comparing the spectroscopic information on the (...)

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[in2p3-00804519] Limited Asymmetry Dependence of Correlations from Single Nucleon Transfer

10 juillet 2015

Single nucleon pickup reactions were performed with a 18:1 MeV=nucleon 14O beam on a deuterium target. Within the coupled reaction channel framework, the measured cross sections were compared to theoretical predictions and analyzed using both phenomenological and microscopic overlap functions. (...)

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[in2p3-01037921] Beta Decay Study of the T-z = -2 $^{56}$Zn Nucleus and the Determination of the Half-Lives of a Few fp-shell Nuclei

10 juillet 2015

This paper concerns the experimental study of the β decay properties of few proton-rich fp -shell nuclei. The nuclei were produced at GANIL in fragmentation reactions, separated with the LISE spectrometer and stopped in an implantation detector surrounded by Ge detectors. The β -delayed gammas, β (...)

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[in2p3-01084779] Resonances in C14 observed in the He4(10Be,α)Be10 reaction

10 juillet 2015

The α(Be10,α)Be10 resonant scattering reaction has been measured at nine Be10 beam energies from 25 to 48 MeV, scanning out resonances in C14 from excitation energies of 13 to 24 MeV. Angular distribution measurements were used to assign the spin and parity of 5− to resonances at Ex=18.82(2) and (...)

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[in2p3-01027507] Observation of a p-wave one-neutron halo configuration in 37Mg

10 juillet 2015

Cross sections of 1n-removal reactions from the neutron-rich nucleus Mg37 on C and Pb targets and the parallel momentum distributions of the Mg37 residues from the C target have been measured at 240 MeV/nucleon. A combined analysis of these distinct nuclear- and Coulomb-dominated reaction data (...)

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[in2p3-00762387] β-delayed neutron emission studies

4 juillet 2015

The study of β-delayed neutron emission plays a major role in different fields such as nuclear technology, nuclear astrophysics and nuclear structure. However the quality of the existing experimental data nowadays is not sufficient for the various technical and scientific applications and new (...)

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[in2p3-00867763] Development of a new neutron time-of-flight array for beta-decay studies

3 juillet 2015

The Nuclear Structure Group of LPC Caen is developing a new neutron time-of-flight detector array for structure studies. Our main physics interest is the investigation of beta-delayed neutron emission from neutron-rich nuclei, including the most exotic cases for which two or more neutrons are (...)

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[in2p3-01025397] Study of states in 14C via the 10Be(4He,4He)10Be reaction

3 juillet 2015

A study of the 10Be(4He,4He)10Be reaction has been performed at 10Be beam energies of 25.0, 27.0, 29.0, 32.0, 34.0, 38.0, 40.0, 42.0, 44.0 and 46.0 MeV. The measurements were to explore possible molecular rotational bands in 14C. Three states at excitation energies of Ex = 18.8, 19.76 and 20.66 (...)

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[in2p3-00966667] Near barrier scattering of 8He on 208Pb

3 juillet 2015

The exotic nucleus 8He is investigated by means of the measurement of the angular distributions of the elastic channel and the 6He and 4He fragment yields produced in the collision with a 208Pb target at two energies around the Coulomb barrier, 16 and 22 MeV. The experiment was performed at the (...)

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[in2p3-00765510] Search for Superscreening effect in Superconductor

3 juillet 2015

The decay of $^19$O($\beta^-$) and $^19$Ne($\beta^+$) implanted in niobium in its superconducting and metallic phase was measured using purified radioactive beams produced by the SPIRAL/GANIL facility. Half-lives and branching ratios measured in the two phases are consistent within one-sigma (...)

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[in2p3-01017235] Neutron occupancy of 0d5/2 orbital in 24O

3 juillet 2015

The partial one-neutron removal cross section of 24O leading to the first excited state in 23O has been measured to be 65.7 ± 5.3 mb with a proton target in inverse kinematics at the beam energy of 62 MeV/nucleon. The decay energy spectrum of the neutron unbound state of 23O was reconstructed (...)

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[in2p3-00804422] Elastic scatterring of the 8He + 208PB at 22 MeV

3 juillet 2015

The dynamics of 8He around the Coulomb barrier is investigated by measuring the energy and angular distribution of the elastic 8He and the 6He and 4He fragment yields in the collision process with a 208Pb target. The experiment was carried out at SPIRAL/GANIL in October 2010. The experimental (...)

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[in2p3-01019156] Structure Beyond the Neutron Drip-Line: 9He

3 juillet 2015

In order to solve the nature of 9He ground state, additional information on this unbound nucleus with extreme N/Z ratio was needed. The present study was performed via the (d,p) reaction, a standard tool for determination of neutron single-particle (...)

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[in2p3-00548964] Emergence of the N=16 shell gap in $^{21}$O

3 juillet 2015

The spectroscopy of 21O has been investigated using a radioactive 20O beam and the (d,p) reaction in inverse kinematics. The ground and first excited states have been determined to be Jpi=5/2+ and Jpi=1/2+ respectively. Two neutron unbound states were observed at excitation energies of 4.76 +- (...)

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[in2p3-00846623] Publisher's Note: In-beam spectroscopic studies of the 44S nucleus [Phys. Rev. C 85, 024311 (2012)]

3 juillet 2015

This paper was published online on 15 February 2012 with errors in Figs. 2 and 4. The figures has been replaced as of 28 February 2012. The figures are correct in the printed version of the journal.

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[in2p3-00630178] Spectroscopy of $^{18}$Na: Bridging the two-proton radioactivity of $^{19}$Mg

3 juillet 2015

The unbound nucleus $^18$Na, the intermediate nucleus in the two-proton radioactivity of $^19$Mg, was studied by the measurement of the resonant elastic scattering reaction $^17$Ne(p,$^17$Ne)p performed at 4 A.MeV. Spectroscopic properties of the low-lying states were obtained in a R-matrix (...)

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[in2p3-00730399] Core excitations and narrow states beyond the proton dripline: The exotic nucleus 21Al

3 juillet 2015

We present the first predictions for the widths of resonance states in a so-far unobserved exotic isotope beyond the proton dripline, 21Al. For this purpose we employ mirror symmetry between the widths of low-lying resonance states and the asymptotic normalization coefficients (ANC) of their (...)

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[in2p3-00642050] Measurement of Unbound Excited States of (24)O

3 juillet 2015

The unbound excited states of the most neutron-rich oxygen isotope, (24)O (Z = 8, N = 16), have been investigated using the (24)O(p,p')(24)O*-->(23)O+n reaction at RIKEN, where a 63 MeV/neuclon secondary beam of (24)O was produced in a Be production target by the projectile-like (...)

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[in2p3-00642092] SHARC: Silicon Highly-segmented Array for Reactions and Coulex used in conjunction with the TIGRESS gamma-ray spectrometer

3 juillet 2015

The combination of gamma-ray spectroscopy and charged-particle spectroscopy is a powerful tool for the study of nuclear reactions with beams of nuclei far from stability. This paper presents a new silicon detector array, SHARC, the Silicon Highly-segmented Array for Reactions and Coulex. The (...)

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[in2p3-00858297] Structure of unbound neutron-rich $^{9}$He studied using single-neutron transfer

3 juillet 2015

The 8He(d,p) reaction was studied in inverse kinematics at 15.4A MeV using the MUST2 Si-CsI array in order to shed light on the level structure of 9He. The well known 16O(d,p)17O reaction, performed here in reverse kinematics, was used as a test to validate the experimental methods. The 9He (...)

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[in2p3-00657202] In-beam spectroscopic studies of $^{44}$S nucleus

3 juillet 2015

The structure of the $^44$S nucleus has been studied at GANIL through the one proton knock-out reaction from a $^45$Cl secondary beam at 42~A$\cdot$MeV. The $\gamma$ rays following the de-excitation of $^44$S were detected in flight using the 70 BaF$_2$ detectors of the Ch\^ateau de Cristal (...)

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[in2p3-00658557] Electrostatic mask for active targets

3 juillet 2015

Active gas targets have been used in nuclear physics since 30 years. They are promising systems in view of the new exotic beams soon available at facilities like SPIRAL2 or FAIR, but the system can still be improved. One of the main limitation is the dynamic range in energy deposition. The (...)

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[in2p3-00654167] Resonances in 19Ne with relevance to the astrophysically important 18F(p,{\alpha})15O reaction

3 juillet 2015

The most intense gamma-ray line observable from novae is likely to be from positron annihilation associated with the decay of 18F. The uncertainty in the destruction rate of this nucleus through the 18F(p,\alpha)15O reaction presents a limit to interpretation of any future observed gamma-ray (...)

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[in2p3-01090228] Neutron occupancy of the 0d5/2 orbital and the N = 16 shell closure in 24O

3 juillet 2015

One-neutron knockout from 24O leading to the first excited state in 23O has been measured for a proton target at a beam energy of 62 MeV/nucleon. The decay energy spectrum of the neutron unbound state of 23O was reconstructed from the measured four momenta of the 22O fragment and emitted (...)

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[in2p3-00817042] Alpha cluster structure in 56Ni

3 juillet 2015

The inelastic $\alpha$−scattering experiment on 56Ni in inverse kinematics was performed at an incident energy of 50 MeV/u at GANIL. A very high multiplicity for $\alpha$−particle emission was observed with our phase-space limited experimental set-up. The maximum observed multiplicity, which (...)

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[in2p3-00920222] Structure of $^{13}$Be probed via secondary beam reactions

3 juillet 2015

The low-lying level structure of the unbound neutron-rich nucleus $^13$Be has been investigated via breakup on a carbon target of secondary beams of $^14,15$B at 35 MeV/nucleon. The coincident detection of the beam velocity $^12$Be fragments and neutrons permitted the invariant mass of the (...)

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[in2p3-01148934] Shape coexistence at N=20 and N=28 : study of 0+2 states in $^{34}$Si and $^{44}$S

3 juillet 2015

It is well known that the nuclear shell structure changes for the most exotic nuclei. One of the consequences of this phenomenon is the modification of the "classical" magic numbers, as experimentally observed at N = 20 and N = 28. Nevertheless, the mechanisms responsible for such (...)

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[in2p3-00702716] Resonances in 19Ne with relevance to the astrophysically important 18F(p,$\alpha$)15O reaction

3 juillet 2015

The main source of gamma ray emission from novae below 511 keV is likely to be associated with the beta+ decay of 18F. The main uncertainty in the abundance of this nucleus comes from the 18F(p,alpha)15O reaction. In 2006, through microscopic techniques, two previously unseen energy levels in (...)

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[in2p3-00411985] TIARA: a large solid angle silicon array for direct reaction studies with radioactive beams

3 juillet 2015

A compact, quasi-4pi position sensitive silicon array, TIARA, designed to study direct reactions induced by radioactive beams in inverse kinematics is described here. The Transfer and Inelastic All-angle Reaction Array (TIARA) consists of 8 resistive-strip silicon detectors forming an octagonal (...)

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[in2p3-00388587] Spectroscopy of 16O using α + 12C resonant scattering in inverse kinematics

3 juillet 2015

A measurement of the α(12C, α) 12C reaction has been performed using resonant scattering with a gas target. Beam energies of 46, 52, 56 and 63 MeV were used to populate resonances in the excitation energy range of 11.6–22.9 MeV in 16O. The angular distributions of the elastic scattering were (...)

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[in2p3-00583596] Structure of 23Al from one-proton breakup reaction and astrophysical implications

3 juillet 2015

The ground state of the proton-rich nucleus 23Al has been studied by one-proton removal on a carbon target at about 50 MeV/nucleon using the EXOGAM + SPEG experimental setup at GANIL. Longitudinal momentum distributions of the 22Mg breakup fragments, inclusive and in coincidence with gamma rays (...)

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[in2p3-00662400] Low-lying neutron f p-shell intruder states in 27Ne

3 juillet 2015

The quenching of the N = 20 shell gap in neutron-rich nuclei is investigated by studying the single-particle structure of 27Ne via neutron transfer using a 26Ne beam. Two low-lying negative-parity intruder states have been observed, the lowest of which is identified as J π = 3/2−, confirming (...)

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[in2p3-00839924] Scattering of 8He on 208Pb at 22 MeV

3 juillet 2015

The skin nucleus 8He is investigated by measuring the angular distribution of the elasticly scattered 8He and the 6,4He fragments produced in the collision with a 208Pb target at 22 MeV, just above the Coulomb barrier. The experiment was carried out at SPIRAL/GANIL in 2010. Here we present (...)

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[in2p3-00638744] Structure of the neutron-rich N = 7 isotones 10Li and 9He

3 juillet 2015

The near threshold structure of the unbound N=7 isotones 10Li and 9He has been investigated using proton removal and breakup from intermediate energy (35 MeV/nucleon) secondary beams of 11Be and 14,15B. The coincident detection of the beam velocity 9Li and 8He fragments and neutrons permitted (...)

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[in2p3-00428984] Spectroscopy of 16O Using alpha+12C Resonant Scattering in Inverse Kinematics

3 juillet 2015

A measurement of the alpha(12C,alpha)12C reaction has been performed using resonant scattering with a gas target. Beam energies of 46, 51, 56 and 63 MeV were used to populate resonances in the excitation energy range of 11.6 to 22.9 MeV in 16O. The angular distributions of the elastic (...)

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[in2p3-00443978] Halo Structure of the Island of Inversion Nucleus 31Ne

3 juillet 2015

The cross sections for single-neutron removal from the very neutron-rich nucleus 31Ne on Pb and C targets have been measured at 230 MeV=nucleon using the RIBF facility at RIKEN. The deduced large Coulomb breakup cross section of 540(70) mb is indicative of a soft E1 excitation. Comparison with (...)

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[in2p3-00752211] Direct mass measurements of 19B, 22C, 29F, 31Ne, 34Na and other light exotic nuclei

3 juillet 2015

We report on direct time-of-flight based mass measurements of 16 light neutron-rich nuclei. These include the first determination of the masses of the Borromean drip-line nuclei $^19$B, $^22$C and $^29$F as well as that of $^34$Na. In addition, the most precise determinations to date for $^23$N (...)

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[in2p3-00658279] Resonances in 11C observed in the 4He(7Be,α)7Be and 4He(7Be,p)10B reactions

3 juillet 2015

Measurements of the 4He(7Be,α)7Be and 4He(7Be,p)10B reactions were performed using 7Be beam energies of 7.1 and 23 MeV and a helium-4 target, employing the thick target technique. Resonances were observed between Ex(11C)=8.6 to 13.8 MeV. An R-matrix analysis was performed to characterize the (...)

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[in2p3-00658293] One and two neutron removal reactions from the most neutron-rich carbon isotopes

3 juillet 2015

The structure of $^19,20,22$C has been investigated using high-energy (about 240 MeV/nucleon) one- and two-neutron removal reactions on a carbon target. Measurements were made of the inclusive cross sections and momentum distributions for the charged residues. Narrow momentum distributions were (...)

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[in2p3-00750395] Evolution of the shell structure in medium-mass nuclei : search for the 2d5/2 neutron orbital in 69Ni

3 juillet 2015

It has been shown that the neutron 2d5/2 orbital has to be included in shell-model calculations to explain the appearance of large quadrupole collectivity observed in the neutron rich Fe and Cr of the N ≈ 40 region. This work initiated by Caurier et al. has been recently revisited. Calculations (...)

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[in2p3-00451414] 6He + 9Be reactions at 16.8 MeV

3 juillet 2015

Reactions of a 16.8 MeV 6He beam with a 9Be target have been investigated using highly segmented detector setup covering a large solid angle. Data on elastic and quasi-free scattering, as well as two-neutron transfer, are reported. The results for elastic scattering are fairly well reproduced (...)

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[in2p3-00578739] Search for 2d5/2 Neutron States in $^{69}$Ni

3 juillet 2015

It has been shown that the neutron 2d5=2 orbital has to be included in shell-model calculations to explain the large quadrupole collectivity observed in the Fe and Cr of N = 40 region, probably a new island of inversion similar to the one known for light nuclei around N = 20. Indeed, in these (...)

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[in2p3-00354511] Low-energy $^{18}$F( p, alpha)$^{15}$O cross section measurements relevant to nova $GAMMA$-ray emission

3 juillet 2015

During nova outbursts the decay of 18F is the main source of γ -ray emission at and below 511 keV. In spite of much experimental effort, the quantity of 18F synthesized still suffers from large uncertainties which arise mainly from the 18F(p, α)15O reaction cross section at low energies.We report (...)

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[in2p3-00977048] Deformation-Driven p-Wave Halos at the Drip Line: 31Ne

3 juillet 2015

The halo structure of Ne31 is studied using 1n-removal reactions on C and Pb targets at 230 MeV/nucleon. A combined analysis of the cross sections of these nuclear and Coulomb dominated reactions that feed directly the Ne30 ground-state reveals Ne31 to have a small neutron separation energy, (...)

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[in2p3-01044774] N=16 Spherical Shell Closure in O-24

3 juillet 2015

The unbound excited states of the neutron drip-line isotope O-24 have been investigated via the O-24(p, p')O-23 + n reaction in inverse kinematics at a beam energy of 62 MeV/nucleon. The decay energy spectrum of O-24* was reconstructed from the momenta of O-23 and the neutron. The spin parity (...)

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[in2p3-01044741] Towards Na-26 via (d,p) with SHARC and TIGRESS and a novel zero-degree detector

3 juillet 2015

Nucleon transfer experiments have in recent years begun to be exploited in the study of nuclei far from stability, using radioactive beams in inverse kinematics. New techniques are still being developed in order to perform these experiments. The present experiment is designed to study the (...)

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[in2p3-01044720] Astrophysically important reaction rates for novae and X‐ray bursts from proton breakup at intermediate energies

3 juillet 2015

We discuss the use of one‐nucleon removal reactions of loosely bound nuclei at intermediate energies as an indirect method in nuclear astrophysics. The breakup reactions are proved to be good spectroscopic tools and can be used to study a large number of loosely bound proton‐ or neutron‐rich (...)

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[in2p3-00467536] The β-γ decay of 21Na

3 juillet 2015

A new and independent determination of the Gamow-Teller branching ratio in the β-decay of 21Na is reported. The value 5.13 ± 0.43% obtained is in agreement with the currently adopted value and the most recent measurement. In contrast to previous experiments, the present method was based on the (...)

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[in2p3-00785481] The N = 16 spherical shell closure in 24O

3 juillet 2015

The unbound excited states of the neutron drip-line isotope 24O have been investigated via the 24O(p,p')23O+n reaction in inverse kinematics at a beam energy of 62 MeV/nucleon. The decay energy spectrum of 24O* was reconstructed from the momenta of 23O and the neutron. The spin-parity of the (...)

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[in2p3-00691971] First measurements with the BEta deLayEd neutron detector (BELEN-20) at JYFLTRAP

3 juillet 2015

A prototype version of the BEta deLayEd Neutron detector, which is being developed for the FAIR/DESPEC experiment, has been used for the first time in an experiment at JYFL (Finland). This detector is based on 3He counters and its first run was primarily intended to commission the detector and (...)

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[in2p3-00384521] Does transfer confirm knockout results for spectroscopic factor suppression with radioactive beams?

3 juillet 2015

Proton removal measurements of the (e, e′p), (d,3He), and fast-beam knockout types show a consistent reduction of the spectroscopic factor when compared to shell model calculations [1-3]. The loss of single-particle strength is explained as the result of the short-range correlations between (...)

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[in2p3-00785471] Comment on "First Observation of Ground State Dineutron Decay: 16Be

3 juillet 2015

A recent measurement [Spyrou et al., PRL 108, 102501 (2012)] of the in-flight decay of 16Be into 14Be+n+n has been interpreted as the first case of dineutron emission. Here we point out that the inclusion of the n-n interaction neglected in the description of the direct three-body decay can (...)

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[in2p3-00675011] Astrophysical($ALPHA$, $GAMMA$) reaction in inverse kinematics; Electron screening effect in the beta-decay

3 juillet 2015

The abundance calculations of the p-nuclei produced in explosive stellar sites rely on the Hauser-Feshbach (HF) theory with the alpha-article optical model potential (α-OMP) one of its major ingredients. To date, most of the (α, γ) cross sections measured show that HF calculations can be wrong by (...)

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[in2p3-00675640] Direct radiative proton capture 23Al(p,$\alpha$)24Si studied via one-proton nuclear breakup of 24Si

3 juillet 2015

We present the results of an experimental work that studied the direct component of the radiative proton capture reaction 23Al(p,$\gamma$)24Si for its relevance in X-ray burst nucleosynthesis. The experiment was performed at GANIL using one-proton nuclear breakup reaction at intermediate (...)

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[in2p3-00924885] Upgrade of the SPIRAL identification station for high-precision measurements of nuclear β decay

3 juillet 2015

The low-energy identification station at SPIRAL (Système de Production d'Ions Radioactifs Accélérés en Ligne) has been upgraded for studying the β decays of short-lived radioactive isotopes and to perform high-precision half-life and branching-ratio measurements for superallowed Fermi and isospin (...)

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[in2p3-01089706] Shape coexistence at N=20 and N=28: Study of 0+2 states in 34Si and 44S

3 juillet 2015

It is well known that the nuclear shell structure changes for the most exotic nuclei. One of the consequences of this phenomenon is the modification of the "classical" magic numbers, as experimentally observed at N = 20 and N = 28. Nevertheless, the mechanisms responsible for such (...)

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[in2p3-00823225] Invariant Mass Spectroscopy of O-23 via the (p, p') Reaction in Inverse Kinematics

3 juillet 2015

The neutron-rich oxygen isotope O-23 has been investigated via proton inelastic scattering on a liquid hydrogen target at 63.5 MeV/nucleon. The invariant mass method in inverse kinematics was employed to reconstruct the energy spectrum. A sharp resonance state was observed at 42(5) keV above (...)

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[in2p3-00619310] Spectroscopy of 39,41Si and the border of the N = 28 island of inversion

3 juillet 2015

The structure of the very neutron-rich nuclei 39Si and 41Si has been investigated via in-beam γ -ray spectroscopy and few-nucleon knockout from radioactive beams. The observation of low-lying states in 39Si is a clear evidence for a drastic lowering of the intruder neutron 3/2− state when going (...)

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[in2p3-00517862] Spectroscopy of the unbound nucleus 18Na

3 juillet 2015

The unbound nucleus 18Na, the intermediate nucleus in the two-proton radioactivity of 19Mg, is studied through the resonant elastic scattering 17Ne(p,17Ne)p. The spectroscopic information obtained in this experiment is discussed and put in perspective with previous measurements and the (...)

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[in2p3-00414084] Exploring the Southern Boundaries of the “Island of Inversion” at the RIBF

3 juillet 2015

The nuclear structure of neutron rich Ne isotopes has been investigated at the recently commissioned Radioactive Ion Beam Factory (RIBF) at the RIKEN Nishina Center by means of inelastic scattering and knockout reactions. A cocktail beam of unstable nuclei around 32Ne was provided by the (...)

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