Fusion barrier distributions in systems with finite excitation energy

Eigen-channel approach to heavy-ion fusion reactions is exact only when the excitation energy of the intrinsic motion is zero. In order to take into account effects of finite excitation energy, we introduce an energy dependence to weight factors in the eigen-channel approximation. Using two channel problem, we show that the weight factors are slowly changing functions of incident energy. This suggests that the concept of the fusion barrier distribution still holds to a good approximation even when the excitation energy of the intrinsic motion is finite. A transition to the adiabatic tunneling, where the coupling leads to a static potential renormalization, is also discussed.Comment: 9 pages, 4 figures, Submitted to Physical Review

Recent experimental results in sub- and near-barrier heavy ion fusion reactions

Recent advances obtained in the field of near and sub-barrier heavy-ion fusion reactions are reviewed. Emphasis is given to the results obtained in the last decade, and focus will be mainly on the experimental work performed concerning the influence of transfer channels on fusion cross sections and the hindrance phenomenon far below the barrier. Indeed, early data of sub-barrier fusion taught us that cross sections may strongly depend on the low-energy collective modes of the colliding nuclei, and, possibly, on couplings to transfer channels. The coupled-channels (CC) model has been quite successful in the interpretation of the experimental evidences. Fusion barrier distributions often yield the fingerprint of the relevant coupled channels. Recent results obtained by using radioactive beams are reported. At deep sub-barrier energies, the slope of the excitation function in a semi-logarithmic plot keeps increasing in many cases and standard CC calculations over-predict the cross sections. This was named a hindrance phenomenon, and its physical origin is still a matter of debate. Recent theoretical developments suggest that this effect, at least partially, may be a consequence of the Pauli exclusion principle. The hindrance may have far-reaching consequences in astrophysics where fusion of light systems determines stellar evolution during the carbon and oxygen burning stages, and yields important information for exotic reactions that take place in the inner crust of accreting neutron stars.Comment: 40 pages, 63 figures, review paper accepted for EPJ

Energy and angular momentum sharing in dissipative collisions

Primary and secondary masses of heavy reaction products have been deduced from kinematics and E-ToF measurements, respectively, for the direct and reverse collisions of 93Nb and 116Sn at 25 AMeV. Light charged particles have also been measured in coincidence with the heavy fragments. Direct experimental evidence of the correlation of energy-sharing with net mass transfer has been found using the information from both the heavy fragments and the light charged particles. The ratio of Hydrogen and Helium multiplicities points to a further correlation of angular momentum sharing with net mass transfer.Comment: 21 pages, 20 figures. Submitted to European Physics Journal

Particle and light fragment emission in peripheral heavy ion collisions at Fermi energies

A systematic investigation of the average multiplicities of light charged particles and intermediate mass fragments emitted in peripheral and semiperipheral collisions is presented as a function of the beam energy, violence of the collision and mass of the system. The data have been collected with the "Fiasco" setup in the reactions 93Nb+93Nb at 17, 23, 30, 38AMeV and 116Sn+116Sn at 30, 38AMeV. The midvelocity emission has been separated from the emission of the projectile-like fragment. This last component appears to be compatible with an evaporation from an equilibrated source at normal density, as described by the statistical code Gemini at the appropriate excitation energy. On the contrary, the midvelocity emission presents remarkable differences for what concerns both the dependence of the multiplicities on the energy deposited in the midvelocity region and the isotopic composition of the emitted light charged particles.Comment: 18 pages, 17 figures, Revtex

Space and Time pattern of mid-velocity IMF emission in peripheral heavy-ion collisions at Fermi energies

The emission pattern in the V_perp - V_par plane of Intermediate Mass Fragments with Z=3-7 (IMF) has been studied in the collision 116Sn + 93Nb at 29.5 AMeV as a function of the Total Kinetic Energy Loss of the reaction. This pattern shows that for peripheral reactions most of IMF's are emitted at mid-velocity. Coulomb trajectory calculations demonstrate that these IMF's are produced in the early stages of the reaction and shed light on geometrical details of these emissions, suggesting that the IMF's originate both from the neck and the surface of the interacting nuclei.Comment: 4 pages, 3 figures, RevTex 3.1, submitted to Phys. Rev. Letter

Charge distributions of Ra recoil ions produced in 12C+Pb fusion-evaporation reactions

Charge state distributions of the Ra recoil ions produced in the 12C+Pb fusion-evaporation reactions have been obtained by measuring their yields as a function of the high voltage applied to an electrostatic deflector. Well-defined two-humped yield curves for evaporation residues (ERs) were observed. Such observations can be explained by the different sets of charge states inherent in Ra recoil ions. These charge sets correspond to the equilibrated and nonequilibrated components, as earlier observed for evaporation residues produced in different reactions. The main parameters of the distributions (mean charge values, widths, and relative intensities) for both components have been estimated using Monte Carlo simulations of the transmission of the Ra recoil ions through the deflector. For the equilibrated component the values of the mean charge and width are close to those given by different empirical systematics. For the nonequilibrated component these parameters have been obtained for the first time. The additional nonequilibrated ionization is presumably due to the formation of inner shell vacancies produced by the internal conversion of nuclear isomeric transitions of ERs. Nonequilibrated charge parameters obtained for Ra recoil ions are compared to similar available experimental data and some theoretical predictions

Formulación y evaluación de un proyecto de inversión para la instalación de un parque fotovoltaico en zona norte de la provincia de San Luis

Existe interés en algunos inversores privados para instalar un parque generador de energía eléctrica a partir de fuentes renovables de energía, en esta ocasión aprovechando la luz del sol como fuente y se hace necesario evaluar la rentabilidad del proyecto de una central Fotovoltaica (FV en adelante) en la provincia de San Luis, Argentina. En la actualidad la generación de energía solar es una actividad de gran desarrollo e interés en países del primer mundo, donde se buscan alternativas amigables con el medio ambiente y que suponen un costo de operación rentable. A la hora de realizar una evaluación de este tipo es necesario un estudio detallado no solo de aspectos financieros, sino también de aspectos técnicos que terminen por aportar información precisa y valiosa para la toma de decisiones. Se estudiarán todas las alternativas en cada componente eligiendo finalmente la opción que garantice la mejor relación calidad precio. Una vez elegidos se buscara el valor de cada uno entregado en el lugar propuesto para la central. Finalmente se estudiará el Cash Flow o Flujo de Fondos con herramientas como el VAN -Valor Actual Neto y la TIR -Tasa Interna de Retorno- entre otros.This paper presents the proposed construction of a PV farm in the north of the province of San Luis, near the town of Luján. With the data provided, we analyzed them by means of specific software as PV Syst and the energy generated was analyzed. Also took into account the costs and financial study to determine the feasibility of installing a central like this.Tema 4: Energía solar, conversión fotovoltaica.Facultad de Arquitectura y Urbanism

Formulación y evaluación de un proyecto de inversión para la instalación de un parque fotovoltaico en zona norte de la provincia de San Luis

Existe interés en algunos inversores privados para instalar un parque generador de energía eléctrica a partir de fuentes renovables de energía, en esta ocasión aprovechando la luz del sol como fuente y se hace necesario evaluar la rentabilidad del proyecto de una central Fotovoltaica (FV en adelante) en la provincia de San Luis, Argentina. En la actualidad la generación de energía solar es una actividad de gran desarrollo e interés en países del primer mundo, donde se buscan alternativas amigables con el medio ambiente y que suponen un costo de operación rentable. A la hora de realizar una evaluación de este tipo es necesario un estudio detallado no solo de aspectos financieros, sino también de aspectos técnicos que terminen por aportar información precisa y valiosa para la toma de decisiones. Se estudiarán todas las alternativas en cada componente eligiendo finalmente la opción que garantice la mejor relación calidad precio. Una vez elegidos se buscara el valor de cada uno entregado en el lugar propuesto para la central. Finalmente se estudiará el Cash Flow o Flujo de Fondos con herramientas como el VAN -Valor Actual Neto y la TIR -Tasa Interna de Retorno- entre otros.This paper presents the proposed construction of a PV farm in the north of the province of San Luis, near the town of Luján. With the data provided, we analyzed them by means of specific software as PV Syst and the energy generated was analyzed. Also took into account the costs and financial study to determine the feasibility of installing a central like this.Tema 4: Energía solar, conversión fotovoltaica.Facultad de Arquitectura y Urbanism

Formulación y evaluación de un proyecto de inversión para la instalación de un parque fotovoltaico en zona norte de la provincia de San Luis

Existe interés en algunos inversores privados para instalar un parque generador de energía eléctrica a partir de fuentes renovables de energía, en esta ocasión aprovechando la luz del sol como fuente y se hace necesario evaluar la rentabilidad del proyecto de una central Fotovoltaica (FV en adelante) en la provincia de San Luis, Argentina. En la actualidad la generación de energía solar es una actividad de gran desarrollo e interés en países del primer mundo, donde se buscan alternativas amigables con el medio ambiente y que suponen un costo de operación rentable. A la hora de realizar una evaluación de este tipo es necesario un estudio detallado no solo de aspectos financieros, sino también de aspectos técnicos que terminen por aportar información precisa y valiosa para la toma de decisiones. Se estudiarán todas las alternativas en cada componente eligiendo finalmente la opción que garantice la mejor relación calidad precio. Una vez elegidos se buscara el valor de cada uno entregado en el lugar propuesto para la central. Finalmente se estudiará el Cash Flow o Flujo de Fondos con herramientas como el VAN -Valor Actual Neto y la TIR -Tasa Interna de Retorno- entre otros.This paper presents the proposed construction of a PV farm in the north of the province of San Luis, near the town of Luján. With the data provided, we analyzed them by means of specific software as PV Syst and the energy generated was analyzed. Also took into account the costs and financial study to determine the feasibility of installing a central like this.Tema 4: Energía solar, conversión fotovoltaica.Facultad de Arquitectura y Urbanism