R. Lichtenthäler - Academia.edu (original) (raw)

Papers by R. Lichtenthäler

Frontiers in Nuclear and Particle Physics, 2018

Exotic nuclei and atomic masses (ENAM 98), 1998

A spectroscopic study of the proton-rich, particle unstable nucleus 11N has been performed using ... more A spectroscopic study of the proton-rich, particle unstable nucleus 11N has been performed using the multi-nucleon transfer reaction 12C(14N,15C)11N at 30 AMeV incident energy at GANIL. Levels of 11N are observed as well defined resonances in the spectrum of the 15C-ejectiles. They are localized at 2.18(5), 3.63(5), 4.39(5), 5.12(8) and 5.87(15) MeV above the 10C+p threshold. The comparison of the measured widths with R-matrix calculations allows the estimation of spins and parities for these resonances.

Physics of Unstable Nuclei, 2008

We present the main characteristics of the recently installed Brazilian radioactive beam facility... more We present the main characteristics of the recently installed Brazilian radioactive beam facility (RIBRAS) and its first results on the elastic scattering and total reaction cross sections for the 6He+ 27A1 system, at near barrier energies, where the role of the nuclear break-up ...

EPJ Web of Conferences, 2014

Experimental cross sections for the 6 He+ 120 Sn are analysed. Elastic scattering angular distrib... more Experimental cross sections for the 6 He+ 120 Sn are analysed. Elastic scattering angular distributions and alpha particle production cross sections have been measured and are compared with the total reaction cross sections.

Nuclear Physics News, 2005

Nuclear physics has been going through a major evolution over the last decade with the possibilit... more Nuclear physics has been going through a major evolution over the last decade with the possibility of producing secondary beams of nuclei far from the stability line (exotic nuclei). Many new facilities have been put to work in order to investigate nuclei at extreme conditions of density, temperature, and with a high number of protons or neutrons. In particular, the possibility of using exotic nuclear beams has opened an exciting field of investigation in nuclear physics with strong implications in nuclear astrophysics.

Nuclear Physics News, 2013

ABSTRACT The availability of radioactive beams provides new opportunities in nuclear physics [1].... more ABSTRACT The availability of radioactive beams provides new opportunities in nuclear physics [1]. On the one hand, they provide a probe of the nuclear structure in unusual conditions of excitation energy and isospin. Many experiments have been performed with beams such as 6He, 8He 11Li, 11Be, among others (see references in Ref. [1]). At energies near the Coulomb barrier or above, these experiments provide valuable information on the structure of exotic nuclei and on the dynamics of the nuclear reactions between them. On the other hand, recent experiments involving radioactive beams have been very successful in nuclear astrophysics, where many stellar scenarios involve short-lived nuclei [2].

EPJ Web of Conferences, 2014

A recent experiment has been performed in the double solenoid system Radioactive Ion Beams in Bra... more A recent experiment has been performed in the double solenoid system Radioactive Ion Beams in Brasil (RIBRAS) by impinging a pure 6 He secondary beam on a thick CH 2 target to measure the 6 He + p excitation function. Results of this experiment will be presented.

EPJ Web of Conferences, 2014

We present the results of experiments using a 6 He beam on a 9 Be target at energies 7 − 9 times ... more We present the results of experiments using a 6 He beam on a 9 Be target at energies 7 − 9 times the Coulomb barrier. Angular distributions of the elastic, inelastic scattering (target breakup) and the α-particle production in the 6 He+ 9 Be collision have been analysed. Total reaction cross sections were obtained from the elastic scattering analyses and a considerable enhancement has been observed by comparing to stable systems.

Physical Review C, 2008

Angular distributions for the 9 Be(8 Li, 9 Be) 8 Li elastic-transfer reaction have been measured ... more Angular distributions for the 9 Be(8 Li, 9 Be) 8 Li elastic-transfer reaction have been measured with a 27-MeV 8 Li radioactive nuclear beam. Spectroscopic factors for the 9 Be| 8 Li + p bound system were obtained from the comparison between the experimental differential cross sections and finite-range distorted-wave Born approximation calculations made with the code FRESCO. The spectroscopic factors so obtained are compared with shell-model calculations and other experimental values. Using the present value for the spectroscopic factors, cross sections and reaction rates for the 8 Li(p, γ) 9 Be direct proton-capture reaction of astrophysical interest were calculated in the framework of the potential model.

AIP Conference Proceedings, 2009

The Radioactive Ion Beams Facility (RIBRAS) is in operation since 2004 at the Pelletron Accelerat... more The Radioactive Ion Beams Facility (RIBRAS) is in operation since 2004 at the Pelletron Accelerator Laboratory of the University of São Paulo and consists of two superconducting solenoids capable of producing low energy secondary beams of light exotic nuclei. Measurements of the elastic scattering, breakup and transfer reactions with radioactive projectiles such as 6 He, 8 Li, 7 Be on several targets have been performed. A review of the research program carried on along the last four years using the RIBRAS facility is presented.

AIP Conference Proceedings, 2010

The elastic scattering data for the 6 He+ 9 Be and 7 Be+ 9 Be reactions, measured at E lab =16.2 ... more The elastic scattering data for the 6 He+ 9 Be and 7 Be+ 9 Be reactions, measured at E lab =16.2 MeV and E lab =23.7 MeV respectively, are presented and analyzed using the optical model and coupled-channels formalisms.

A part of the research program developed in the RIBRAS facility over the last four years is prese... more A part of the research program developed in the RIBRAS facility over the last four years is presented. Experiments using radioactive secondary beams of light exotic nuclei such as 6 He, 7 Be, 8 Li on several targets have been performed. Elastic angular distributions have been analysed by the Optical Model and four body Continuous Discretized Coupled Channels Calculations (4b-CDCC) and the total reaction cross sections have been obtained. A comparison between the reaction cross sections of 6 He and other stable projectiles with medium-heavy targets was performed. Measurements of the proton transfer reaction 12 C(8 Li, 9 Be) 11 B are also presented.

Measurements of the p(6 He,p) elastic scattering excitation function have been performed in the R... more Measurements of the p(6 He,p) elastic scattering excitation function have been performed in the RIBRAS system using a 6 He secondary beam and a CH 2 polyethylene thick target. The motivation is to observe states of the compound nucleus 7 Li in the excitation energy range of E 7 Li exc = 10.8 − 11.8MeV, where the isobaric analog state of 7 He ground state lies. Excitation functions have been obtained at three laboratory angles θ lab = 0 • , 20 • , and 25 • which correspond to θ c.m = 180 • , 140 • , and 130 • .

AIP Conference Proceedings, 2012

ABSTRACT Abstract: The RIBRAS facility (Radiactive Ion Beams in Brasil) is installed next to the ... more ABSTRACT Abstract: The RIBRAS facility (Radiactive Ion Beams in Brasil) is installed next to the 8 MV Pelletron Tandem of the Nuclear Physics Laboratory of the Institute of Physics of the University of Sao Paulo. It consists of two superconducting solenoids with maximum magnetic field of B=6.5T. Light radioactive ion beams are produced through transfer reactions, using solid or gaseous production targets of Be, LiF, He-3 etc. The solenoids make a magnetic rigidity selection and the use of the two solenoids with a degrader between them allows the production of quite pure secondary beams. Beams of He-6, Li-8, Be-7, Be-10, B-8, B-12 are currently produced and used to study elastic, inelastic, and transfer reactions on a variety of light, medium mass and heavy secondary targets. Some examples of reactions recently studied are presented below.

A description of the double solenoid system (RIBRAS) operating since 2004 in one of the beam line... more A description of the double solenoid system (RIBRAS) operating since 2004 in one of the beam lines of the Pelletron Laboratory of the Institute of Physics of the University of Sao Paulo is presented. The recent installation of the secondary scattering chamber after the second solenoid is reported and the first experiment in RIBRAS using both solenoids is described.

Physics Letters B, 2001

The charge and mass transition matrix elements of the neutron-rich isotopes 30,32 Mg have been ex... more The charge and mass transition matrix elements of the neutron-rich isotopes 30,32 Mg have been extracted from inelastic scattering on 208 Pb and 12 C targets at 32 A MeV. The measured inelastic cross sections for the first 2 + states were compared to coupled-channels calculations, which take into account the feeding from higher excited states. The method was tested with 24 Mg inelastic scattering data obtained in the same experiment. In the framework of the rotational model, the charge and mass deformations are identical and large (|β| ∼ 0.5-0.6) for both isotopes.

Physical Review C, 1996

The binary decay into strongly damped fragments and the quasielastic reactions of the ²⁸Si+¹â... more The binary decay into strongly damped fragments and the quasielastic reactions of the ²⁸Si+¹⁶O system were measured at {ital E}{sub lab}=107.5 and 139.0 MeV in the angular range of 30°â¤Î¸{sub c.m.}â¤150° using kinematic coincidence. The loss in the binary decay cross section due to light particle evaporation by the highly excited fragments was evaluated. The {ital Q}-value-integrated angular distributions of

Physical Review C, 2006

Angular distributions for the 11 B+ 25 Mg elastic scattering, 25 Mg(11 B, 12 C) 24 Na proton pick... more Angular distributions for the 11 B+ 25 Mg elastic scattering, 25 Mg(11 B, 12 C) 24 Na proton pickup, and 25 Mg(11 B, 10 Be) 26 Al stripping reactions have been measured at E11 B = 35 MeV. The angular distributions have been analyzed by the distorted-waves Born approximation calculations using the code fresco. The spectroscopic factors for the overlaps 25 Mg| 26 Al , 25 Mg| 24 Na for the ground state and excited states of 26 Al and 24 Na have been obtained and compared to previous measurements and shell-model calculations.

Physical Review C, 2002

... Laird,4 L. Maunoury,5 GF Lima,1,3 F. de Oliveira Santos,5 P. Roussel-Chomaz,5 H. Savajols,5 W... more ... Laird,4 L. Maunoury,5 GF Lima,1,3 F. de Oliveira Santos,5 P. Roussel-Chomaz,5 H. Savajols,5 W. Trinder,5 ACC Villari,5 and A ... Among their interesting aspects, we can cite the inversion of the normal shell model ordering for energy levels, for example, the lowering of the ...

Frontiers in Nuclear and Particle Physics, 2018

Exotic nuclei and atomic masses (ENAM 98), 1998

A spectroscopic study of the proton-rich, particle unstable nucleus 11N has been performed using ... more A spectroscopic study of the proton-rich, particle unstable nucleus 11N has been performed using the multi-nucleon transfer reaction 12C(14N,15C)11N at 30 AMeV incident energy at GANIL. Levels of 11N are observed as well defined resonances in the spectrum of the 15C-ejectiles. They are localized at 2.18(5), 3.63(5), 4.39(5), 5.12(8) and 5.87(15) MeV above the 10C+p threshold. The comparison of the measured widths with R-matrix calculations allows the estimation of spins and parities for these resonances.

Physics of Unstable Nuclei, 2008

We present the main characteristics of the recently installed Brazilian radioactive beam facility... more We present the main characteristics of the recently installed Brazilian radioactive beam facility (RIBRAS) and its first results on the elastic scattering and total reaction cross sections for the 6He+ 27A1 system, at near barrier energies, where the role of the nuclear break-up ...

EPJ Web of Conferences, 2014

Experimental cross sections for the 6 He+ 120 Sn are analysed. Elastic scattering angular distrib... more Experimental cross sections for the 6 He+ 120 Sn are analysed. Elastic scattering angular distributions and alpha particle production cross sections have been measured and are compared with the total reaction cross sections.

Nuclear Physics News, 2005

Nuclear physics has been going through a major evolution over the last decade with the possibilit... more Nuclear physics has been going through a major evolution over the last decade with the possibility of producing secondary beams of nuclei far from the stability line (exotic nuclei). Many new facilities have been put to work in order to investigate nuclei at extreme conditions of density, temperature, and with a high number of protons or neutrons. In particular, the possibility of using exotic nuclear beams has opened an exciting field of investigation in nuclear physics with strong implications in nuclear astrophysics.

Nuclear Physics News, 2013

ABSTRACT The availability of radioactive beams provides new opportunities in nuclear physics [1].... more ABSTRACT The availability of radioactive beams provides new opportunities in nuclear physics [1]. On the one hand, they provide a probe of the nuclear structure in unusual conditions of excitation energy and isospin. Many experiments have been performed with beams such as 6He, 8He 11Li, 11Be, among others (see references in Ref. [1]). At energies near the Coulomb barrier or above, these experiments provide valuable information on the structure of exotic nuclei and on the dynamics of the nuclear reactions between them. On the other hand, recent experiments involving radioactive beams have been very successful in nuclear astrophysics, where many stellar scenarios involve short-lived nuclei [2].

EPJ Web of Conferences, 2014

A recent experiment has been performed in the double solenoid system Radioactive Ion Beams in Bra... more A recent experiment has been performed in the double solenoid system Radioactive Ion Beams in Brasil (RIBRAS) by impinging a pure 6 He secondary beam on a thick CH 2 target to measure the 6 He + p excitation function. Results of this experiment will be presented.

EPJ Web of Conferences, 2014

We present the results of experiments using a 6 He beam on a 9 Be target at energies 7 − 9 times ... more We present the results of experiments using a 6 He beam on a 9 Be target at energies 7 − 9 times the Coulomb barrier. Angular distributions of the elastic, inelastic scattering (target breakup) and the α-particle production in the 6 He+ 9 Be collision have been analysed. Total reaction cross sections were obtained from the elastic scattering analyses and a considerable enhancement has been observed by comparing to stable systems.

Physical Review C, 2008

Angular distributions for the 9 Be(8 Li, 9 Be) 8 Li elastic-transfer reaction have been measured ... more Angular distributions for the 9 Be(8 Li, 9 Be) 8 Li elastic-transfer reaction have been measured with a 27-MeV 8 Li radioactive nuclear beam. Spectroscopic factors for the 9 Be| 8 Li + p bound system were obtained from the comparison between the experimental differential cross sections and finite-range distorted-wave Born approximation calculations made with the code FRESCO. The spectroscopic factors so obtained are compared with shell-model calculations and other experimental values. Using the present value for the spectroscopic factors, cross sections and reaction rates for the 8 Li(p, γ) 9 Be direct proton-capture reaction of astrophysical interest were calculated in the framework of the potential model.

AIP Conference Proceedings, 2009

The Radioactive Ion Beams Facility (RIBRAS) is in operation since 2004 at the Pelletron Accelerat... more The Radioactive Ion Beams Facility (RIBRAS) is in operation since 2004 at the Pelletron Accelerator Laboratory of the University of São Paulo and consists of two superconducting solenoids capable of producing low energy secondary beams of light exotic nuclei. Measurements of the elastic scattering, breakup and transfer reactions with radioactive projectiles such as 6 He, 8 Li, 7 Be on several targets have been performed. A review of the research program carried on along the last four years using the RIBRAS facility is presented.

AIP Conference Proceedings, 2010

The elastic scattering data for the 6 He+ 9 Be and 7 Be+ 9 Be reactions, measured at E lab =16.2 ... more The elastic scattering data for the 6 He+ 9 Be and 7 Be+ 9 Be reactions, measured at E lab =16.2 MeV and E lab =23.7 MeV respectively, are presented and analyzed using the optical model and coupled-channels formalisms.

A part of the research program developed in the RIBRAS facility over the last four years is prese... more A part of the research program developed in the RIBRAS facility over the last four years is presented. Experiments using radioactive secondary beams of light exotic nuclei such as 6 He, 7 Be, 8 Li on several targets have been performed. Elastic angular distributions have been analysed by the Optical Model and four body Continuous Discretized Coupled Channels Calculations (4b-CDCC) and the total reaction cross sections have been obtained. A comparison between the reaction cross sections of 6 He and other stable projectiles with medium-heavy targets was performed. Measurements of the proton transfer reaction 12 C(8 Li, 9 Be) 11 B are also presented.

Measurements of the p(6 He,p) elastic scattering excitation function have been performed in the R... more Measurements of the p(6 He,p) elastic scattering excitation function have been performed in the RIBRAS system using a 6 He secondary beam and a CH 2 polyethylene thick target. The motivation is to observe states of the compound nucleus 7 Li in the excitation energy range of E 7 Li exc = 10.8 − 11.8MeV, where the isobaric analog state of 7 He ground state lies. Excitation functions have been obtained at three laboratory angles θ lab = 0 • , 20 • , and 25 • which correspond to θ c.m = 180 • , 140 • , and 130 • .

AIP Conference Proceedings, 2012

ABSTRACT Abstract: The RIBRAS facility (Radiactive Ion Beams in Brasil) is installed next to the ... more ABSTRACT Abstract: The RIBRAS facility (Radiactive Ion Beams in Brasil) is installed next to the 8 MV Pelletron Tandem of the Nuclear Physics Laboratory of the Institute of Physics of the University of Sao Paulo. It consists of two superconducting solenoids with maximum magnetic field of B=6.5T. Light radioactive ion beams are produced through transfer reactions, using solid or gaseous production targets of Be, LiF, He-3 etc. The solenoids make a magnetic rigidity selection and the use of the two solenoids with a degrader between them allows the production of quite pure secondary beams. Beams of He-6, Li-8, Be-7, Be-10, B-8, B-12 are currently produced and used to study elastic, inelastic, and transfer reactions on a variety of light, medium mass and heavy secondary targets. Some examples of reactions recently studied are presented below.

A description of the double solenoid system (RIBRAS) operating since 2004 in one of the beam line... more A description of the double solenoid system (RIBRAS) operating since 2004 in one of the beam lines of the Pelletron Laboratory of the Institute of Physics of the University of Sao Paulo is presented. The recent installation of the secondary scattering chamber after the second solenoid is reported and the first experiment in RIBRAS using both solenoids is described.

Physics Letters B, 2001

The charge and mass transition matrix elements of the neutron-rich isotopes 30,32 Mg have been ex... more The charge and mass transition matrix elements of the neutron-rich isotopes 30,32 Mg have been extracted from inelastic scattering on 208 Pb and 12 C targets at 32 A MeV. The measured inelastic cross sections for the first 2 + states were compared to coupled-channels calculations, which take into account the feeding from higher excited states. The method was tested with 24 Mg inelastic scattering data obtained in the same experiment. In the framework of the rotational model, the charge and mass deformations are identical and large (|β| ∼ 0.5-0.6) for both isotopes.

Physical Review C, 1996

The binary decay into strongly damped fragments and the quasielastic reactions of the ²⁸Si+¹â... more The binary decay into strongly damped fragments and the quasielastic reactions of the ²⁸Si+¹⁶O system were measured at {ital E}{sub lab}=107.5 and 139.0 MeV in the angular range of 30°â¤Î¸{sub c.m.}â¤150° using kinematic coincidence. The loss in the binary decay cross section due to light particle evaporation by the highly excited fragments was evaluated. The {ital Q}-value-integrated angular distributions of

Physical Review C, 2006

Angular distributions for the 11 B+ 25 Mg elastic scattering, 25 Mg(11 B, 12 C) 24 Na proton pick... more Angular distributions for the 11 B+ 25 Mg elastic scattering, 25 Mg(11 B, 12 C) 24 Na proton pickup, and 25 Mg(11 B, 10 Be) 26 Al stripping reactions have been measured at E11 B = 35 MeV. The angular distributions have been analyzed by the distorted-waves Born approximation calculations using the code fresco. The spectroscopic factors for the overlaps 25 Mg| 26 Al , 25 Mg| 24 Na for the ground state and excited states of 26 Al and 24 Na have been obtained and compared to previous measurements and shell-model calculations.

Physical Review C, 2002

... Laird,4 L. Maunoury,5 GF Lima,1,3 F. de Oliveira Santos,5 P. Roussel-Chomaz,5 H. Savajols,5 W... more ... Laird,4 L. Maunoury,5 GF Lima,1,3 F. de Oliveira Santos,5 P. Roussel-Chomaz,5 H. Savajols,5 W. Trinder,5 ACC Villari,5 and A ... Among their interesting aspects, we can cite the inversion of the normal shell model ordering for energy levels, for example, the lowering of the ...