General behavior of the effective nucleon-nucleon interaction as a function of the relative velocity

We have studied volume integrals of the central part of optical potentials extracted from data analyses for a variety of light and heavy systems. The data-extracted integrals present a quite simple behavior as a function of the relative velocity between target and projectile. This behavior is system independent and, therefore, it reflects a feature of the effective nucleon-nucleon interaction itself. The overall results are in good agreement with the predictions of the São Paulo potential, which is a model for the nuclear interaction that so far has been employed mostly in analyses of heavy-ion reactions

Investigation of Coulomb dipole polarization effects on reactions involving exotic nuclei

We have analyzed elastic scattering angular distributions and total reaction cross sections of the exotic nuclei Li9,11 on Pb208, at energies below and above the Coulomb barrier. For this purpose, we have used an optical potential with no adjustable parameters, composed by the nuclear São Paulo potential, derived from the nonlocal nature of the interaction, and the Coulomb dipole polarization potential, derived from the semiclassical theory of Coulomb excitation. Within this formalism, we identified an unusual long-range absorption for the Li11+Pb208 system, which is dominated by the Coulomb interaction. We compare it to the absorption mechanisms observed for He6+Pb208 which, unlike those of Li11+Pb208, take place at small interacting distances, where both Coulomb and nuclear interactions are important. The proposed approach shows to be a fundamental basis to study reactions involving exotic nuclei

Simultaneous analysis of elastic, breakup, and fusion channels for 6He induced reactions at energies near the coulomb barrier

5th International Conference FUSION11We present some recent applications of the Continuum-Discretized Coupled-Channels (CDCC) and Coupled-Reaction-Channels (CRC) methods to the study of reactions induced by weakly-bound nuclei on stable targets. The methods are applied to the scattering of the Borromean nucleus 6He at energies around the Coulomb barrier. Elastic scattering data are very well described by four-body CDCC calculations (based on a three-body description of the 6He nucleus) but also by simpler three-body CDCC calculations, using a suitable two-body model for 6He. By contrast, inclusive α data are better described using the CRC approach, which treats the breakup within the transfer to the continuum picture and, unlike the CDCC method, allows the inclusion of transfer to bound states of the target. We explore also the possibility of calculating the fusion cross sections using the CRC frameworkMinisterio de Ciencia e Innovación FPA2009-0765

The 6He Optical Potential at energies around the Coulomb barrier

We present an Optical Model (OM) study of 6He on 208Pb elastic scattering data, measured at laboratory energies around the Coulomb barrier (Elab=14, 16, 18, 22, and 27 MeV) [1]. For the projectile-target bare interaction, we use the microscopic São Paulo Potential (SPP). This bare interaction is supplemented with a Coulomb Dipole Polarization (CDP) potential, as well as a diffuse complex Woods-Saxon potential. Four-body Continuum-Discretized-Coupled-Channels (CDCC) calculations have been performed in order to support the optical model analysis. We have also studied the α channel, which is the dominant reaction process. In the analysis of this channel, we compare the angular and energy distributions of the α particles measured at 22 MeV, with Distorted Wave Born Approximation (DWBA) calculations

Development of a tracking system of exotic nuclear beams for FAIR

New accelerators like SPIRAL2 (GANIL, France) or FAIR (GSI, Germany) will be soon constructed, and they will be able to produce radioactive ion beams (RIB) with high intensities of current (≥106pps). These beams, at low energy, lower than 20 MeV/n, usually have high emittance, which imposes the use of tracking detectors before the target in order to reconstruct the trajectory of the ions. The group of Nuclear Physics at CNA (Centro Nacional de Aceleradores), is in charge of developing a tracking system for the low energy branch of FAIR (the HISPEC/DESPEC project). A collaboration with CEA-SACLAY was established, with the aim of developing, building and testing low pressure Secondary electron Detectors (SeD). Within this proposal we have projected and constructed a new Nuclear Physics Line in the CNA in order to be able to receive any kind of detector tests and the associated nuclear instruments

Sprachenpolitik als Sicherheitsproblem in der Ukraine

This paper presents the design, implementation, and measurements of a complete electronic frontend intended for high-resolution spatial detection of ion beams at counting rates higher than 106 particles per second (p/s). The readout system is made up of three main multichannel building blocks, namely, a transimpedance preamplifier, a signal-conditioning line receiver, and a charge-to-digital converter, as well as some off-the-shelf components. The preamplifier and the line receiver have been specifically designed and optimized to minimize the overlapping probability of ion beams tracking, at high counting rates, in low-pressure gaseous secondary electron detectors. Experimental results are shown, considering α particles sources and particles beams, featuring an adaptive shaping time frame of 170-230 ns with a peak signal-to-noise ratio of up to 25 dB. These performance metrics are competitive with the state of the art, demonstrating the suitability of the reported data acquisition and instrumentation system for precise and fast particle tracking detection

γ spectroscopy of 25 , 27 Ne and 26 , 27 Na

The γ spectroscopy of 25, 27 Ne and 26, 27 Na was studied from the reaction of 26 Ne with a deuterium target in inverse kinematics at 9.7 MeV/nucleon. The selectivity of the (d,p), (d,t), and (d,n) transfer reactions provides new spectroscopic information on low-lying states. The validity of the sd shell-model space for these nuclei isdiscussed

Systematic calculations of reactions with exotic and stable nuclei to establish a unified theoretical approach

We report on systematical optical model (OM) and continuum discretized coupled channel (CDCC) calculations applied to describe the elastic scattering angular distributions of exotic and stable nuclei projectiles on heavy targets. Our optical potential (OP) is composed of the nuclear microscopic double folding São Paulo potential (SPP), derived from the nonlocal nature of the interaction, and the Coulomb dipole polarization (CDP) potential, derived from the semiclassical theory of Coulomb excitation. The OP is compared to the trivial equivalent local potential (TELP), extracted from CDCC calculations. The OM and CDCC predictions corroborate each other and account for important differences in the nuclei reaction mechanisms, which are directly related to their structural properties. Thus, OM and CDCC establish a common basis for analyzing or even predicting exotic and stable nuclei reactions.Ministerio de Ciencia, Innovación y Universidades de España. PGC2018-096994-B-C21Ministerio de Economía y Competitividad de España y el Fondo Europeo de Desarrollo Regional (FEDER) FIS2017-88410-PPrograma de investigación e innovación Horizonte 2020 de la Unión Europea ,No. 654002Fondos SID 2019 (Investimento Strategico di Dipartimento, Universittí degli Studi di Padova, Italia) CASA_SID19_0

Development of Slowed Down Beams at the Fragment Separator for FAIR

The feasibility studies of the slowed down beam setup involving deceleration of a 64Ni beam at 250 MeV/u to 13 MeV/u in a thick Al degrader was performed at the FRagment Separator (FRS) at GSI. The experimentally measured energy spread and the nuclear reaction yields in the degrader are in good agreement with simulations

Two-neutron transfer in the 6 He + 120 Sn reaction

A large yield of α particles produced in the 120 Sn ( 6 He , α ) reaction was measured at 20.3-, 22.2-, 22.4-, and 24.5-MeV bombarding energies. The α particles are distributed over a broad energy range in the vicinity and below the elastic scattering 6 He peak. Energy integrated α -particle cross sections have been obtained at θ lab = 36 ∘ , 40 ∘ , and 60 ∘ . The α energy distributions have been analyzed at a fixed laboratory angle ( ≈ 60 ∘ ) in terms of the reaction Q value, considering the 2 n -transfer reaction kinematics 120 Sn ( 6 He , α ) 122 Sn . A kinematical analysis of the Q -value distribution shows that the recoil system 120 Sn + 2 n is formed in highly excited states in the continuum, at increasing excitation energies as the bombarding energy increases. It is shown that by using Brink's formula, the excitation energy depends on the transferred angular momentum following a linear relation with the square of the angular momentum, indicating that some kind of dinuclear rotating system is formed after the reaction.Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq/MCTI de Brasil y Fundação de Amparo à Pesquisa do Estado de São Paulo. Brasil–FAPESP. 2013/22100-7 y 2014/19666-1VI Plan Propio de Investigación de la Universidad de Sevilla (2017-2018