134 research outputs found

    Proton halo effects in the 8B+64Zn collision around the Coulomb barrier

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    The 8B+64Zn reaction at 38.5 MeV has been studied at HIE-ISOLDE CERN to investigate proton halo effect on the reaction dynamics. For the first time it was used the only existing post-accelerated 8B beam. The measured elastic scattering angular distribution showed a small suppression of the Coulomb-nuclear interference peak, opposite to what observed for the one-neutron halo nucleus 11Be on the same target where a large suppression was observed instead. Inclusive angular and energy distributions of breakup fragments were also measured showing that, both, elastic and non-elastic breakup contribute. The presence of the additional Coulomb interactions halo-core and halo-target in 8B makes the reaction dynamics in this proton-halo nucleus different than the neutron-halo case

    Study of elastic and inelastic scattering of 7Be + 12C at 35 MeV

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    The elastic and inelastic scattering of 7Be from 12C have been measured at an incident energy of 35 MeV. The inelastic scattering leading to the 4.439 MeV excited state of 12C has been measured for the first time. The experimental data cover an angular range of θcm= 15◦-120◦. Optical model analyses were carried out with Woods-Saxon and double-folding potential using the density dependent M3Y (DDM3Y) effective interaction. The microscopic analysis of the elastic data indicates breakup channel coupling effect. A coupled-channel analysis of the inelastic scattering, based on collective form factors, shows thatmutual excitation of both 7Be and 12C is significantly smaller than the single excitation of 12C. The larger deformation length obtained from the DWBA analysis could be explained by including the excitation of 7Be in a coupled-channel analysis. The breakup cross section of 7Be is estimated to be less than 10%of the reaction cross section. The intrinsic deformation length obtained for the 12C∗(4.439 MeV) state is δ2= 1.37 fm. The total reaction cross section deduced from the analysis agrees very well with Wong’s calculations for similar weakly bound light nuclei on 12C target.The authors thank the ISOLDE engineers in charge, RILIS team and Target Group at CERN for their support. D. Gupta acknowledges research funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 654002 (ENSAR2) and ISRO, Government of India under grant no. ISRO/RES/2/378/15-16. O. Tengblad would like to acknowledge the support by the Spanish Funding Agency (AEI / FEDER, EU) under the project PID2019-104390GB-I00. I. Martel would like to acknowledge the support by the Ministry of Science, Innovation and Universities of Spain (Grant No. PGC2018-095640-B-I00). J. Cederkall acknowledges grants from the Swedish Research Council (VR) under contract numbers VR-2017-00637 and VR-2017- 03986 as well as grants from the Royal Physiographical Society. J. Park would like to acknowledge the support by Institute for Basic Science (IBS-R031-D1). S. Szwec acknowledges support by the Academy of Finland (Grant No. 307685). A.M.M. is supported by the I+D+i project PID2020-114687GB-I00 funded by MCIN/AEI/10.13039/501100011033, by the grant Group FQM-160 and by project P20_01247, funded by the Consejería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía (Spain) and by “ERDF A way of making Europe”

    Resonance Excitations in 7Be(d,p)8Be*to Address the Cosmological Lithium Problem

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    The anomaly in lithium abundance is a well-known unresolved problem in nuclear astrophysics. A recent revisit to the problem tried the avenue of resonance enhancement to account for the primordial 7 Li abundance in standard big-bang nucleosynthesis. Prior measurements of the 7 Be ( d , p ) 8 Be * reaction could not account for the individual contributions of the different excited states involved, particularly at higher energies close to the Q value of the reaction. We carried out an experiment at HIE-ISOLDE, CERN to study this reaction at E c . m . = 7.8 MeV , populating excitations up to 22 MeV in 8 Be for the first time. The angular distributions of the several excited states have been measured and the contributions of the higher excited states in the total cross section at the relevant big-bang energies were obtained by extrapolation to the Gamow window using the talys code. The results show that by including the contribution of the 16.63 MeV state, the maximum value of the total S factor inside the Gamow window comes out to be 167 MeV b as compared to earlier estimate of 100 MeV b. However, this still does not account for the lithium discrepancy.The authors thank the ISOLDE engineers in charge, RILIS team and Target Group at CERN for their support. D. G. acknowledges research funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 654002 (ENSAR2) and ISRO, Government of India under Grant No. ISRO/RES/2/378/15-16. O. T. would like to acknowledge the support by the Spanish Funding Agency (AEI/FEDER, EU) under the project PID2019-104390GB-I00. I. M. would like to acknowledge the support by the Ministry of Science, Innovation and Universities of Spain (Grant No. PGC2018-095640-B-I00). J. C. acknowledges grants from the Swedish Research Council (VR) under Contracts No. VR-2017-00637 and No. VR-2017-03986 as well as grants from the Royal Physiographical Society. J. P. would like to acknowledge the support by Institute for Basic Science (IBS-R031-D1). S. S. acknowledges support by the Academy of Finland (Grant No. 307685)

    Theranostic: a new tecnique againts cancer

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    Theranostic, has positioned itself as a promising technique to fight cancer, especially when using radioactive isotopes, where it has demonstrated good efficiency in human cancer treatment and in the animal phase study. The technique basically consists in using a chemical element with several radioactive isotopes. One diagnostic (gamma or β+ emitter) and another isotope of the same therapeutic element (alpha, β+, β- or Auger electrons). These isotopes must be linked to a vector molecule expressed by the tumor cells of the corresponding type of cancer. Radioisotopes can also be encapsulated in nanoparticles

    Simultaneous analysis of the elastic scattering and breakup channel for the reaction 11Li + 208Pb at energies near the Coulomb barrier

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    We present a detailed analysis of the elastic scattering and breakup channel for the reaction of 11Li on 208Pb at incident laboratory energies of 24.3 and 29.8 MeV, measured at the radioactive ion beam facility of TRIUMF, in Vancouver, Canada. A large yield of 9Li fragments was detected by four charged particle telescopes in a wide angular range. The experimental angular and energy distributions of these 9Li fragments have been compared to coupled-reaction-channel and continuum-discretized coupled-channel calculations. The large production of 9Li fragments at small angles can be explained by considering a direct breakup mechanism, while at medium-large angles a competition between direct breakup and neutron transfer to the continuum of the 208Pb target was observed

    A clear signature of the breakup modes for 9Be on a proton target at 5.6 MeV/nucleon

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    The breakup of 9Be is studied via an inelastic scattering experiment on a proton target at 5.6 A MeV in inverse kinematics. Two of the three cluster constituents (α and α) as well as the proton target recoil were recorded in a triple coincidence mode allowing a full kinematics approach analysis. In this respect relative α - α and α - n, Q-value and 9Be excitation spectra, energy spectra for all fragments as well as the energy spectrum of the recoil proton were reconstructed. A clear signature of the two breakup sequential modes (5He + 4He and 8Be + n) was identified via the recoiling proton reconstructed spectra together with the direct breakup decay. A strong 5He + 4He mode was observed compatible with previous beta decay experiments

    Spectroscopy of proton-unbound nuclei by tracking their decay products in-flight: One- and two-proton decays of 15F, 16Ne, and 19Na

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    14 páginas, 23 figuras, 1 tabla.-- et al.A powerful method of investigating proton-unbound nuclear states by tracking their decay products in flight is discussed in detail. To verify the method, four known levels in 15F, 16Ne, and 19Na were investigated by measuring the angular correlations between protons and the respective heavy-ion fragments stemming from the precursor decays in flight. The parent nuclei of interest were produced in nuclear reactions of one-neutron removal from 17Ne and 20Mg projectiles at energies of 410–450 A MeV. The trajectories of the respective decay products, 14O + p + p and 18Ne + p + p, were measured by applying a tracking technique with microstrip detectors. These data were used to reconstruct the angular correlations of the fragments, which provided information on energies and widths of the parent states. In addition for reproducing properties of known states, evidence for hitherto unknown excited states in 15F and 16Ne was found. This tracking technique has an advantage in studies of exotic nuclei beyond the proton drip line measuring the resonance energies and widths with a high precision although by using low-intensity beams and very thick targets.This work has been supported by Contract EURONS Nos. EC-I3 and FPA2006-13807-C02-01, FPA2007-63074 (MEC, Spain), the INTAS Grant No. 03-54-6545. L.V.G. is supported by FAIR-Russia Research Center grant, Russian Foundation for Basic Research viaGrant Nos. RFBR 08-02-00892 and 08-02-00089-a, and Russian Ministry of Industry and Science Grant No. NSh-7235.2010.2. N.K.T. acknowledges support from the UK Grant No. STFC ST/F012012/1, E.L. is supported by the LOEWE program of the State of Hessen (Helmholtz International Center for FAIR), Germany.Peer Reviewe

    Observation and Spectroscopy of New Proton-Unbound Isotopes 30Ar and 29Cl: An Interplay of Prompt Two-Proton and Sequential Decay

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    Previously unknown isotopes Ar30 and Cl29 have been identified by measurement of the trajectories of their in-flight decay products S28+p+p and S28+p, respectively. The analysis of angular correlations of the fragments provided information on decay energies and the structure of the parent states. The ground states of Ar30 and Cl29 were found at 2.25+0.15−0.10 and 1.8±0.1  MeV above the two- and one-proton thresholds, respectively. The lowest states in Ar30 and Cl29 point to a violation of isobaric symmetry in the structure of these unbound nuclei. The two-proton decay has been identified in a transition region between simultaneous two-proton and sequential proton emissions from the Ar30 ground state, which is characterized by an interplay of three-body and two-body decay mechanisms. The first hint of a fine structure of the two-proton decay of Ar∗30(2+) has been obtained by detecting two decay branches into the ground and first-excited states of the S28 fragment.A. G., S. K., S. R., and P. S. were supported by the Helmholtz Association Grant No. IK-RU-002. L. V. G. was partly supported by the Ministry of Education and Science of the Russian Federation Grant No. NSh- 932.2014.2. A. F., A. G., L. V. G., S. K., P. S., and R. S. were partly supported by the Russian Foundation for Basic Research Grant No. 14-02-00090-a. This work was partly supported by the Polish National Science Center under Contract No. UMO-2011/01/B/ST2/01943. A. A. C. acknowledges support by the Polish Ministry of Science and Higher Education by Grant No. 0079/DIA/ 2014/43 (Grant Diamentowy). M. P. and X. X. are grateful for a support from the Helmholtz International Center for FAIR (HIC for FAIR). Y. L. was supported by the Helmholtz-CAS Joint Research Group Grant No. HCJRG- 108. J. M. E. acknowledges support from the FPA2009- 08848 contract (MICINN, Spain
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