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Accueil > Recherche & Enseignement

Mme Lynda Achouri

Chercheur CNRS

Groupe : Structure nucléaire

achouri lpccaen.in2p3.fr

TEL : +33 2 31 45 25 17


PUBLICATIONS

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

18 février 2017

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

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

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

3 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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[in2p3-01222563] 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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[in2p3-01179429] Isoscalar response of $^{68}$Ni to $\alpha$-particle and deuteron probes

3 septembre 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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[in2p3-00023307] Beta-decay properties of $^{25}$Si and $^{26}$P

3 juillet 2015

The $\beta$-decay properties of the neutron-deficient nuclei $^25$Si and $^26$P have been investigated at the GANIL/LISE3 facility by means of charged-particle and $\gamma$-ray spectroscopy. The decay schemes obtained and the Gamow-Teller strength distributions are compared to shell-model (...)

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[in2p3-00025562] $\alpha:2n:\alpha$ molecular band in $^{10}$Be

3 juillet 2015

The 10.15 MeV resonance in $^10$Be has been probed via resonant $^6$He+$^4$He elastic scattering. It is demonstrated that it is the J$^p$i=4$^+$ member of a rotational band built on the 6.18 MeV 0$^+ $state. A Gammaalpha of 0.10–0.13 MeV and Gammaalpha/Gamma=0.35–0.46 were deduced. The (...)

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[in2p3-00024152] Study of $^{19} $Na at SPIRAL

3 juillet 2015

The excitation function for the elastic-scattering reaction p18Ne, p18Ne was measured with the first radioactive beam from the SPIRAL facility at the GANIL laboratory and with a solid cryogenic hydrogen target. Several broad resonances have been observed, corresponding to new excited states in (...)

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[in2p3-00023405] Observation of bound excited states in $^{15}$B

3 juillet 2015

The structure of the A/Z = 3 nucleus $^15$B has been investigated using the in-beam $\gamma$ -spectroscopy technique with a fragmentation reaction of a $^36$S beam on a $^9$Be target at 77.5 MeV. The fragments were identified and selected by their energy loss and time of flight using the SPEG (...)

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[in2p3-00025120] Search for neutron excitations across the N=20 shell gap in $^{25-29}$Ne

3 juillet 2015

Nuclear structure of the neutron rich $^25-29$Ne nuclei has been investigated through the in-beam $\gamma$-ray spectroscopy technique using fragmentation reactions of both stable and radioactive beams. Level schemes have been deduced for these Ne isotopes. In order to examine the importance of (...)

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[in2p3-00024673] The $^7Be(d,p)2\alpha$ cross section at Big Bang energies and the primordial $^7$Li abundance

1er juillet 2015

The WMAP satellite, devoted to the observations of the anisotropies of the Cosmic Microwave Background (CMB) radiation, has recently provided a determination of the baryonic density of the Universe with unprecedented precision. Using this, Big Bang Nucleosynthesis (BBN) calculations predict a (...)

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

20 mai 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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Structure of 13Be probed via secondary-beam reactions

27 mars 2014

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

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

18 décembre 2013

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

19 juillet 2013

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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Alpha cluster structure in 56Ni

23 avril 2013

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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Study of neutron rich nucleus 25F via single-step fragmentation

25 mars 2013

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

6 février 2013

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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[in2p3-00765510] Search for Superscreening effect in Superconductor

14 décembre 2012

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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[in2p3-00762387] β-delayed neutron emission studies

7 décembre 2012

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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Neutron and charged particle identification by means of various detectors

11 septembre 2012

Identification methods for photons, neutrons and heavy ions by using scintillator and semiconductor detectors are discussed by stressing the advantages of signal digitization.

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[in2p3-00719389] One-proton breakup of 24Si and the 23Al( p, γ )24Si reaction in type I x-ray bursts

19 juillet 2012

To understand explosive hydrogen burning in stars and to explore various explosive scenarios such as type I x-ray bursts (XRBs), reliable reaction rates are needed. The cross sections for radiative proton capture on near-dripline nuclei are necessary for the determination of the reaction rates, (...)

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

31 mai 2012

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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First measurements with the BEta deLayEd neutron detector (BELEN-20) at JYFLTRAP

27 avril 2012

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

28 février 2012

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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Low-energy F18(p, α)O15 cross section measurements relevant to nova γ-ray emission

16 février 2012

During nova outbursts the decay of F18 is the main source of γ-ray emission at and below 511 keV. In spite of much experimental effort, the quantity of F18 synthesized still suffers from large uncertainties which arise mainly from the F18(p, α)O15 reaction cross section at low energies. We report (...)

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

24 janvier 2012

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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Resonances in 11C observed in the 4He(7Be,α)7Be and 4He(7Be,p)10B reactions

10 janvier 2012

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

10 janvier 2012

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

6 janvier 2012

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

21 décembre 2011

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

21 décembre 2011

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

17 novembre 2011

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

17 novembre 2011

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

7 octobre 2011

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

7 octobre 2011

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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Spectroscopy of 39,41Si and the border of the N = 28 island of inversion

6 septembre 2011

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

6 septembre 2011

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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Emergence of the N = 16 shell gap in $^{21}$O

11 juillet 2011

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 J π= 5/2+ and 1/2+, respectively. Two neutron unbound states were observed at excitation energies of 4.77(10) (...)

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Structure of 23Al from one-proton breakup reaction and astrophysical implications

6 avril 2011

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

6 avril 2011

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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Emergence of the N=16 shell gap in $^{21}$O

21 décembre 2010

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

21 décembre 2010

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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Direct measurement of the 18F(p,alpha)15O reaction for application to nova gamma-ray emission

25 novembre 2010

The 18F nucleus is one of the radioactive isotopes produced during nova explosions. It is of particular interest since it is mainly responsible for the 511 keV gamma-ray emission of novae that could be detected with the INTEGRAL satellite or future gamma-ray telescopes. The amount of 18F (...)

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Direct measurement of the 18F(p,alpha)15O reaction for application to nova gamma-ray emission

25 novembre 2010

The 18F nucleus is one of the radioactive isotopes produced during nova explosions. It is of particular interest since it is mainly responsible for the 511 keV gamma-ray emission of novae that could be detected with the INTEGRAL satellite or future gamma-ray telescopes. The amount of 18F (...)

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Shell and shapes in the $^{44}S nucleus

25 octobre 2010

The results obtained from electron and in-beam spectroscopy experiments reveal that the 44S nucleus is located in a transitional region between the spherical 48Ca and the oblate 42Si. The comparison of the results with Large Scale Shell Model calculations points towards prolate-spherical shape (...)

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Shell and shapes in the $^{44}S nucleus

25 octobre 2010

The results obtained from electron and in-beam spectroscopy experiments reveal that the 44S nucleus is located in a transitional region between the spherical 48Ca and the oblate 42Si. The comparison of the results with Large Scale Shell Model calculations points towards prolate-spherical shape (...)

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Spectroscopy of the unbound nucleus $^{18}$Na

15 septembre 2010

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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Spectroscopy of the unbound nucleus 18Na

15 septembre 2010

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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Cluster States in 12C and 14C

23 août 2010

The cluster structure of 12C is explored and recent measurements of proton inelastic scattering, suggesting a 2+ state close to 9.6 MeV are presented. Resonant scattering studies of 10Be + 4He used to populate resonances in 14C are briefly (...)

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Cluster States in 12C and 14C

23 août 2010

The cluster structure of 12C is explored and recent measurements of proton inelastic scattering, suggesting a 2+ state close to 9.6 MeV are presented. Resonant scattering studies of 10Be + 4He used to populate resonances in 14C are briefly (...)

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Prolate-Spherical Shape Coexistence at N=28 in $^{44}$S

28 juillet 2010

The structure of $^44$S has been studied using delayed $\gamma$ and electron spectroscopy at \textscganil. The decay rates of the 0$^+_2$ isomeric state to the 2$^+_1$ and 0$^+_1$ states have been measured for the first time, leading to a reduced transition probability (...)

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[in2p3-00506598] Prolate-Spherical Shape Coexistence at N=28 in $^{44}$S

28 juillet 2010

The structure of $^44$S has been studied using delayed $\gamma$ and electron spectroscopy at \textscganil. The decay rates of the 0$^+_2$ isomeric state to the 2$^+_1$ and 0$^+_1$ states have been measured for the first time, leading to a reduced transition probability (...)

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The β–γ decay of 21Na

12 avril 2010

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

12 avril 2010

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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Migration of nuclear shell gaps studied in the d(24Ne,p gamma)25Ne reaction

12 avril 2010

The transfer of neutrons onto 24Ne has been measured using a reaccelerated radioactive beam of 24Ne to study the (d,p) reaction in inverse kinematics. The unusual raising of the first 3/2+ level in 25Ne and its significance in terms of the migration of the neutron magic number from N=20 to N=16 (...)

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[in2p3-00472413] Migration of nuclear shell gaps studied in the d(24Ne,p gamma)25Ne reaction

12 avril 2010

The transfer of neutrons onto 24Ne has been measured using a reaccelerated radioactive beam of 24Ne to study the (d,p) reaction in inverse kinematics. The unusual raising of the first 3/2+ level in 25Ne and its significance in terms of the migration of the neutron magic number from N=20 to N=16 (...)

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Low-lying isomeric levels in $^{75}$Cu

15 mars 2010

Isomeric low-lying states were identified and investigated in the 75Cu nucleus. Two states at 61.8(5)- and 128.3(7)-keV excitation energies with half-lives of 370(40)- and 170(15)-ns were assigned as 75m1Cu and 75m2Cu, respectively. The measured half-lives combined with the recent spin (...)

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[in2p3-00463848] Low-lying isomeric levels in $^{75}$Cu

15 mars 2010

Isomeric low-lying states were identified and investigated in the 75Cu nucleus. Two states at 61.8(5)- and 128.3(7)-keV excitation energies with half-lives of 370(40)- and 170(15)-ns were assigned as 75m1Cu and 75m2Cu, respectively. The measured half-lives combined with the recent spin (...)

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Structure around the island of inversion with single-neutron knockout reactions at GANIL

20 janvier 2010

The nuclear structure of the 31Mg nucleus has been studied with the singleneutron knockout reaction. We report on the preliminary results of an experiment performed with the EXOGAM array coupled, for the first time, to the SPEG spectrometer at GANIL.We present a provisional result for the (...)

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Structure around the island of inversion with single-neutron knockout reactions at GANIL

20 janvier 2010

The nuclear structure of the 31Mg nucleus has been studied with the singleneutron knockout reaction. We report on the preliminary results of an experiment performed with the EXOGAM array coupled, for the first time, to the SPEG spectrometer at GANIL.We present a provisional result for the (...)

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Study of the $^{20}$O(d,t) reaction with the TIARA-MUST2-VAMOS-EXOGAM setup

6 janvier 2010

The reaction 20O(d,t) has been studied in inverse kinematics using a secondary ra- dioactive beam produced with the SPIRAL facility at GANIL. Fragments, light charged particles and gamma rays were measured with the TIARA, MUST2, VAMOS and EX- OGAM detectors and preliminary results are reported. (...)

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Study of the $^{20}$O(d,t) reaction with the TIARA-MUST2-VAMOS-EXOGAM setup

6 janvier 2010

The reaction 20O(d,t) has been studied in inverse kinematics using a secondary ra- dioactive beam produced with the SPIRAL facility at GANIL. Fragments, light charged particles and gamma rays were measured with the TIARA, MUST2, VAMOS and EX- OGAM detectors and preliminary results are reported. (...)

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Spectroscopy of 16O Using alpha+12C Resonant Scattering in Inverse Kinematics

30 octobre 2009

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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Spectroscopy of 16O Using alpha+12C Resonant Scattering in Inverse Kinematics

30 octobre 2009

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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TIARA: a large solid angle silicon array for direct reaction studies with radioactive beams

31 août 2009

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

31 août 2009

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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Spectroscopy of 16O using α + 12C resonant scattering in inverse kinematics

27 mai 2009

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

27 mai 2009

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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Does transfer confirm knockout results for spectroscopic factor suppression with radioactive beams?

15 mai 2009

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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Does transfer confirm knockout results for spectroscopic factor suppression with radioactive beams?

15 mai 2009

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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New low-energy measurement of the 18F(p,α)15O reaction

23 avril 2009

The 18F, produced during nova explosions, is the main responsible for the 511 keV γ-ray emitted during the outburst that could be detected with satellite missions or future γ-ray telescopes. In spite of many experimental efforts, the amount of 18F synthesized still suffers from large uncertainties (...)

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New low-energy measurement of the 18F(p,α)15O reaction

23 avril 2009

The 18F, produced during nova explosions, is the main responsible for the 511 keV γ-ray emitted during the outburst that could be detected with satellite missions or future γ-ray telescopes. In spite of many experimental efforts, the amount of 18F synthesized still suffers from large uncertainties (...)

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Recent results from GANIL

30 mars 2009

The shell structure of the nucleus implies the existence of magic numbers. Since several years many indications have been accumulated, theoretically as well as through experiments at various laboratories around the world, that if one moves away from stability, the location of the magic numbers (...)

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Recent results from GANIL

30 mars 2009

The shell structure of the nucleus implies the existence of magic numbers. Since several years many indications have been accumulated, theoretically as well as through experiments at various laboratories around the world, that if one moves away from stability, the location of the magic numbers (...)

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Discovery of a new broad resonance in $^{19}$Ne: Implications for the destruction of the cosmic $\gamma-ray emitter $^{18}$F

25 mars 2009

Six proton-emitting states in 19Ne were studied through the inelastic scattering reaction H(19Ne; p)19Ne*(p)18F. Their energies and widths were derived from the protons detected at zero degree, while proton-proton angular correlations between the detector at zero degree and a segmented annular (...)

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[in2p3-00370811] Discovery of a new broad resonance in $^{19}$Ne: Implications for the destruction of the cosmic $\gamma$-ray emitter $^{18}$F

25 mars 2009

Six proton-emitting states in 19Ne were studied through the inelastic scattering reaction H(19Ne; p)19Ne*(p)18F. Their energies and widths were derived from the protons detected at zero degree, while proton-proton angular correlations between the detector at zero degree and a segmented annular (...)

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Measurement of the Gamow-Teller Branching Ratio in the $\beta$-Decay of ${21}$Na

17 mars 2009

The beta-decay branching ratio of the GT transition in 21Na to the first excited state in 21Ne has been measured. The value obtained of 4.93(20)% is in agreement with the most recent measurement and with the value adopted so far. This confirms that the branching ratio is not the source of (...)

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Measurement of the Gamow-Teller Branching Ratio in the $\beta$-Decay of ${21}$Na

17 mars 2009

The beta-decay branching ratio of the GT transition in 21Na to the first excited state in 21Ne has been measured. The value obtained of 4.93(20)% is in agreement with the most recent measurement and with the value adopted so far. This confirms that the branching ratio is not the source of (...)

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Beta-delayed proton decay of proton-rich nuclei 23Al and 31Cl and explosive H-burning in classical novae

3 février 2009

We have developed a technique to measure beta-delayed proton decay of proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A&M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and (...)

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Beta-delayed proton decay of proton-rich nuclei 23Al and 31Cl and explosive H-burning in classical novae

3 février 2009

We have developed a technique to measure beta-delayed proton decay of proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A&M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and (...)

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

20 janvier 2009

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

20 janvier 2009

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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Structure of the brunnian nucleus $^{10}$C

13 novembre 2008

The 2 ALPHA+ 2p breakup and structure of the only known Brunnian nucleus, 10C, has been studied at 33.3 MeV/nucleon. Detection of the 2ALPHA + 2p breakup fragments using a highly segmented Si-Si-Si-CsI detector array has allowed the 10C -> 9B -> p, 9B -> 8Be + p, 8Be -> (...)

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Structure of the brunnian nucleus $^{10}$C

13 novembre 2008

The 2 ALPHA+ 2p breakup and structure of the only known Brunnian nucleus, 10C, has been studied at 33.3 MeV/nucleon. Detection of the 2ALPHA + 2p breakup fragments using a highly segmented Si-Si-Si-CsI detector array has allowed the 10C -> 9B -> p, 9B -> 8Be + p, 8Be -> (...)

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In-beam gamma-ray spectroscopy of the neutron-rich nitrogen isotopes $^{19-22}$N

28 avril 2008

The structure of $^19-22$N nuclei was investigated by means of in-beam gamma-ray spectroscopic technique using fragmentation reactions of both stable and radioactive beams. Based on particle-gamma and particle-gammagamma coincidence data, level schemes are constructed for the neutron-rich (...)

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[in2p3-00276198] In-beam gamma-ray spectroscopy of the neutron-rich nitrogen isotopes $^{19-22}$N

28 avril 2008

The structure of $^19-22$N nuclei was investigated by means of in-beam gamma-ray spectroscopic technique using fragmentation reactions of both stable and radioactive beams. Based on particle-gamma and particle-gammagamma coincidence data, level schemes are constructed for the neutron-rich (...)

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Single-Proton Removal Reaction Study of $^{16}$B

29 février 2008

The low-lying level structure of the unbound system $^16$B has been investigated via single-proton removal from a 35 MeV/nucleon $^17$C beam. The coincident detection of the beam velocity $^15$B fragment and neutron allowed the relative energy of the in-flight decay of $^16$B to be (...)

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[in2p3-00259696] Single-Proton Removal Reaction Study of $^{16}$B

29 février 2008

The low-lying level structure of the unbound system $^16$B has been investigated via single-proton removal from a 35 MeV/nucleon $^17$C beam. The coincident detection of the beam velocity $^15$B fragment and neutron allowed the relative energy of the in-flight decay of $^16$B to be (...)

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Evidence for core excitation in single-particle states of $^{19}$Na

5 février 2008

We present an experimental study of $^19$Na states in the excitation energy range between 2 and 3 MeV. The presence of $^19$Na single-particle levels at these energies was first predicted by a microscopic cluster model and then experimentally confirmed by measuring the elastic and inelastic (...)

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[in2p3-00202877] Evidence for core excitation in single-particle states of $^{19}$Na

5 février 2008

We present an experimental study of $^19$Na states in the excitation energy range between 2 and 3 MeV. The presence of $^19$Na single-particle levels at these energies was first predicted by a microscopic cluster model and then experimentally confirmed by measuring the elastic and inelastic (...)

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Breakup reaction study of the Brunnian nucleus $^{10}$C

5 février 2008

The structure and 2α + 2p breakup of $^10$C, the only known Brunnian nucleus, has been studied at 33.3 MeV/nucleon. The breakup kinematics were used to reconstruct the $^10$C→$^9$B +p, $^9$B→$^8$Be +p, $^8$Be→ α + α and $^10$C → $^6$Be +α, $^6$Be → $^5$Li +p, $^5$Li → α + p decay paths. Proton emission (...)

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[in2p3-00238356] Breakup reaction study of the Brunnian nucleus $^{10}$C

5 février 2008

The structure and 2α + 2p breakup of $^10$C, the only known Brunnian nucleus, has been studied at 33.3 MeV/nucleon. The breakup kinematics were used to reconstruct the $^10$C→$^9$B +p, $^9$B→$^8$Be +p, $^8$Be→ α + α and $^10$C → $^6$Be +α, $^6$Be → $^5$Li +p, $^5$Li → α + p decay paths. Proton emission (...)

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Etude de la radioactivité de $^{22}$Al et spectroscopie par diffusion élastique résonante

28 août 2007

Ce travail de thèse s'inscrit dans le cadre général de l'étude de la structure des noyaux radioactifs riches en protons. Il se compose de deux parties.<br /> La première partie est consacrée à l'étude de la décroissance Β- particules retardées de 22Al. L'expérience décrite dans cette partie a (...)

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Etude de la radioactivité de $^{22}$Al et spectroscopie par diffusion élastique résonante

28 août 2007

Ce travail de thèse s'inscrit dans le cadre général de l'étude de la structure des noyaux radioactifs riches en protons. Il se compose de deux parties.<br /> La première partie est consacrée à l'étude de la décroissance Β- particules retardées de 22Al. L'expérience décrite dans cette partie a (...)

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First observation of $^{19}$Na states by inelastic scattering

12 juillet 2007

Low-energy states of the 19Na proton-drip nucleus have been investigated by resonant elastic and inelastic scattering in inverse kinematics at the RIB facility at Louvain-la-Neuve, Belgium.We have used a 66 MeV 18Ne beam and a proton-rich (CH2)n target. Recoil protons were detected at forward (...)

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First observation of $^{19}$Na states by inelastic scattering

12 juillet 2007

Low-energy states of the 19Na proton-drip nucleus have been investigated by resonant elastic and inelastic scattering in inverse kinematics at the RIB facility at Louvain-la-Neuve, Belgium.We have used a 66 MeV 18Ne beam and a proton-rich (CH2)n target. Recoil protons were detected at forward (...)

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Collapse of the N=28 shell closure in $^{42}$Si

9 mai 2007

The energies of the excited states in very neutron-rich $^42$Si and $^41,43$P have been measured using in-beam$gamma$-ray spectroscopy from the fragmentation of secondary beams of $^42,44$S at 39 A.MeV. The low $2^+ $ energy of $^42$Si, 770(19) keV, together with the level schemes of $^41,43$P (...)

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[in2p3-00145207] Collapse of the N=28 shell closure in $^{42}$Si

9 mai 2007

The energies of the excited states in very neutron-rich $^42$Si and $^41,43$P have been measured using in-beam$gamma$-ray spectroscopy from the fragmentation of secondary beams of $^42,44$S at 39 A.MeV. The low $2^+ $ energy of $^42$Si, 770(19) keV, together with the level schemes of $^41,43$P (...)

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Primordial $^{7}$Li abundance and the role of the $^{7}$Be(d,p)2$ALPHA$ reaction

15 septembre 2006

Using the recent very precise value of the baryonic density of the Universe [1] and the rates of the reactions involved in the standard Big Bang nucleosynthesis from a new compilation [2], we have deduced the light element (D, $^3$He, $^4$He, $^7$Li) primordial abundances and compared them with (...)

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Primordial $^{7}$Li abundance and the role of the $^{7}$Be(d,p)2$ALPHA$ reaction

15 septembre 2006

Using the recent very precise value of the baryonic density of the Universe [1] and the rates of the reactions involved in the standard Big Bang nucleosynthesis from a new compilation [2], we have deduced the light element (D, $^3$He, $^4$He, $^7$Li) primordial abundances and compared them with (...)

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The beta-decay of 22Al

22 août 2006

In an experiment performed at the LISE3 facility of GANIL, we studied the decay of $^22$Al produced by the fragmentation of a $^36$Ar primary beam. The $\beta$-decay half-life and $\beta$-delayed one- and twoproton emission as well as by $\beta-\alpha$ and $\beta$-delayed $\gamma$ decay were (...)

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[in2p3-00089710] The beta-decay of 22Al

22 août 2006

In an experiment performed at the LISE3 facility of GANIL, we studied the decay of $^22$Al produced by the fragmentation of a $^36$Ar primary beam. The $\beta$-decay half-life and $\beta$-delayed one- and twoproton emission as well as by $\beta-\alpha$ and $\beta$-delayed $\gamma$ decay were (...)

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Isomeric island in the vicinity of $^{66}$Fe

21 juillet 2006

An island of isomers have recently been observed on both sides of the N=40 shell below the Ni isotopes. Isomeric states in the $^65$Fe and $^67$Fe allow the knowledge of the single particle structure around the $\nu$g_9/2$ shell. Moreover, the excitation energy of the first $2^+$ and $4^+$ (...)

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Isomeric island in the vicinity of $^{66}$Fe

21 juillet 2006

An island of isomers have recently been observed on both sides of the N=40 shell below the Ni isotopes. Isomeric states in the $^65$Fe and $^67$Fe allow the knowledge of the single particle structure around the $\nu$g_9/2$ shell. Moreover, the excitation energy of the first $2^+$ and $4^+$ (...)

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Spectroscopy of the proton drip-line nucleus $^{19}$Na by resonant elastic and inelastic scattering

21 juillet 2006

Low-lying states of $^19$Na were investigated using both elastic and inelastic scattering of a $^18$Ne beam on a $(CH_2)_n$ target. The experimental method is briefly described. Preliminary results are presented.

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Spectroscopy of the proton drip-line nucleus $^{19}$Na by resonant elastic and inelastic scattering

21 juillet 2006

Low-lying states of $^19$Na were investigated using both elastic and inelastic scattering of a $^18$Ne beam on a $(CH_2)_n$ target. The experimental method is briefly described. Preliminary results are presented.

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Spectroscopy Near the N=20 Shell Closure: $\beta$-n Decay Studies of $^{33}$Mg and $^{35}$Al

21 juillet 2006

An experimental spectroscopic investigation of some neutron rich Mg and Al isotopes around the shell closure N=20 has been performed. The delayed neutron and $\gamma$ spectra, following the $\beta$-decay of $^33$Mg and $^35$Al have been measured using the delayed neutron detector array TONNERRE (...)

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Spectroscopy Near the N=20 Shell Closure: $\beta$-n Decay Studies of $^{33}$Mg and $^{35}$Al

21 juillet 2006

An experimental spectroscopic investigation of some neutron rich Mg and Al isotopes around the shell closure N=20 has been performed. The delayed neutron and $\gamma$ spectra, following the $\beta$-decay of $^33$Mg and $^35$Al have been measured using the delayed neutron detector array TONNERRE (...)

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Study of $^{19}$Na at SPIRAL

18 juillet 2006

The excitation function for the elastic scattering reaction p($^18$Ne,p)$^18$Ne was measured with the first radioactive beam from the SPIRAL facility at the GANIL laboratory and with a solid cryogenic hydrogen target. Several broad resonances were observed, corresponding to new excited states (...)

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Study of $^{19}$Na at SPIRAL

18 juillet 2006

The excitation function for the elastic scattering reaction p($^18$Ne,p)$^18$Ne was measured with the first radioactive beam from the SPIRAL facility at the GANIL laboratory and with a solid cryogenic hydrogen target. Several broad resonances were observed, corresponding to new excited states (...)

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$\alpha:2n:\alpha$ molecular band in $^{10}$Be

6 février 2006

The 10.15 MeV resonance in $^10$Be has been probed via resonant $^6$He+$^4$He elastic scattering. It is demonstrated that it is the J$^p$i=4$^+$ member of a rotational band built on the 6.18 MeV 0$^+ $state. A Gammaalpha of 0.10–0.13 MeV and Gammaalpha/Gamma=0.35–0.46 were deduced. The (...)

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Search for neutron excitations across the N=20 shell gap in $^{25-29}$Ne

24 novembre 2005

Nuclear structure of the neutron rich $^25-29$Ne nuclei has been investigated through the in-beam $\gamma$-ray spectroscopy technique using fragmentation reactions of both stable and radioactive beams. Level schemes have been deduced for these Ne isotopes. In order to examine the importance of (...)

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Spectroscopy around N = 20 shell closure: $\beta$–n decay study of $^{35}$Al

10 octobre 2005

An experimental spectroscopic investigation of $^35$Al has been performed. The delayed neutron and $gamma$ spectra, following the $\beta$ decay of $^35$Al, have been measured using the delayed neutron detector array TONNERRE coupled with high efficiency $\gamma$ detectors. A detailed analysis (...)

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Observation of the $0^+_2$ state in $^{44}$S

28 septembre 2005

We report preliminary results on the observation of the isomeric $0^+_2$ state in $^44$S. This state, populated in the fragmentation of a $^48$Ca beam, is located at 1365$\pm$1 keV and has a half-life of 2.3$\pm$0.3 $\mu$s. The observation of this isomer is the first experimental evidence of (...)

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The $^7Be(d,p)2\alpha$ cross section at Big Bang energies and the primordial $^7$Li abundance

26 septembre 2005

The WMAP satellite, devoted to the observations of the anisotropies of the Cosmic Microwave Background (CMB) radiation, has recently provided a determination of the baryonic density of the Universe with unprecedented precision. Using this, Big Bang Nucleosynthesis (BBN) calculations predict a (...)

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Study of 19Na at SPIRAL

5 septembre 2005

The excitation function for the elastic-scattering reaction p18Ne, p18Ne was measured with the first radioactive beam from the SPIRAL facility at the GANIL laboratory and with a solid cryogenic hydrogen target. Several broad resonances have been observed, corresponding to new excited states in (...)

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Study of $^7$Be+d reactions for Standard Big Bang Nucleosynthesis

27 juin 2005

The recent WMAP results tightly constrain the baryon density in the universe, which in turn constrains the light element abundance predicted in Standard Big Bang Nucleosynthesis (SBBN). There is a discrepance in the $^7$Li abundance which cannot be explained by uncertainties in the main (...)

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Nuclear Structure around the N=16 subshell closure

21 janvier 2005

In-beam gamma-spectroscopy using fragmentation reactions of both stable and radioactive beams have been performed in order to study the structure of excited states in the neutron-rich 18,20C, 21–24O and 23,25F isotopes. For the produced fragments, gamma-ray energies, intensities and gammagamma (...)

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Observation of bound excited states in $^{15}$B

22 décembre 2004

The structure of the A/Z = 3 nucleus $^15$B has been investigated using the in-beam $\gamma$ -spectroscopy technique with a fragmentation reaction of a $^36$S beam on a $^9$Be target at 77.5 MeV. The fragments were identified and selected by their energy loss and time of flight using the SPEG (...)

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Beta-decay properties of $^{25}$Si and $^{26}$P

15 novembre 2004

The $\beta$-decay properties of the neutron-deficient nuclei $^25$Si and $^26$P have been investigated at the GANIL/LISE3 facility by means of charged-particle and $\gamma$-ray spectroscopy. The decay schemes obtained and the Gamow-Teller strength distributions are compared to shell-model (...)

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