Angular momentum dependence of the GDR width in Sn nuclei at fixed excitation energy

Abstract High-energy γ-rays from the decay of the giant-dipole resonance (GDR) in the hot 106Sn compound nucleus and its daughters were measured in coincidence with heavy recoiling evaporation residues. The compound nucleus was formed at excitation energy E ∗ = 80 MeV using the reaction 56Ni+48Ti at a bombarding energy of 260 MeV. The analysis yields the GDR width for two different intervals of angular momentum 〈J〉 = 24 and 36ℏ. The present data, combined with previous data at higher angular momentum permit a study of the angular momentum dependence of the GDR width for 10 ⩽ J ⩽ 60ℏ at approximately fixed temperature. The width of the GDR is found to be roughly constant for

Effect of E1 decay in the population of superdeformed structures

Abstract Spectra of the yrast and excited superdeformed bands, forming the E2 quasi-continuum, are measured with the EUROBALL array for the nucleus 143 Eu, in coincidence with high-energy γ-rays (Eγ>3 MeV). It is found that the intensity population of the superdeformed states is enhanced by a factor of ≈1.6 when a coincidence with a γ-ray with energy >6 MeV is required, in reasonable agreement with the increase of the line shape of the Giant Dipole Resonance built on a superdeformed configuration. This result shows that when an high energy E1 γ-ray is involved in the decay it is more likely connected with a SD rather than a ND nucleus. In addition, the analysis of the rotational quasi-continuum suggests the presence of a superdeformed component. The data are also compared and found consistent with simulation calculations of the relative intensities of the SD states, including the E1 decay of superdeformed nature

Quantum tunneling of the excited rotational bands in the superdeformed nucleus 143Eu

The properties of the thermally excited rotational motion up to the region of rotational damping are studied experimentally in the superdeformed nucleus 143 Eu. The effective lifetime of the excited discrete rotational bands forming ridge structures in ‐ matrices is measured at the EUROBALL array using the DSAM technique, giving a quadrupole momentQt 10 e b, consistent with the deformation of the superdeformed yrast band. In addition, the effective number of excited superdeformed bands is extracted by a statistical analysis of the ridge structure, for transition energies down to the region where the effect of the decay-out into the normal deformed well shows up. The experimental data are compared with microscopic cranked shell model calculations including a residual interaction of surface delta type. Satisfactory agreement between data and theory is obtained when the quantum tunneling of the excited superdeformed states is included in the model. © 2001 Published by Elsevier Science B.V

The rotational γ-continuum in the mass region A≈110

Abstract Unresolved γ transitions of 114 Te and of 112 Sn sorted into one-dimensional and two-dimensional spectra have been studied. The reaction 64 Ni + 54 Cr at bombarding energies 230, 240, 250, 260, 270 MeV was used and the γ -rays were detected with the EUROBALL array. In the case of the nucleus 114 Te the values of the multiplicity as a function of bombarding energy and of the moment of inertia were obtained. The effective moment of inertia was found to be almost constant in the interval I=20 – 40 ℏ , in contrast to the decreasing behaviour of the dynamic moment of inertia for the terminating yrast band. The ridge valley structures in E γ 1 ×E γ 2 spectra of 114 Te and of 112 Sn were analysed with the fluctuation analysis technique. The analysis of the two nuclei are compared to simulations based on microscopic cranking calculations with residual interactions included. A rather good agreement is found between data and predictions

International Standard ISO 9001–A Soft Computing View

In order to add value to ISO 9001, a Quality Management Systems that assess, measure, documents, improves, and certify processes to increase productivity, i.e., that transforms business at any level. On the one hand, this work focuses on the development of a decision support system, which will allow companies to be able to meet the needs of customers by fulfilling requirements that reflect either the effectiveness or the non-effectiveness of an organization. On the other hand, many approaches for knowledge representation and reasoning have been proposed using Logic Programming (LP), namely in the area of Model Theory or Proof Theory. In this work it is followed the proof theoretical approach in terms of an extension to the LP language to knowledge representation and reasoning. The computational framework is centered on Artificial Neural Networks to evaluate customer’s satisfaction and the degree of confidence that one has on such a happening

Population of neutron-rich nuclei around 48ca with deep inelastic collisions

The deep inelastic reaction 48Ca+64Ni at 6 MeV/A has been studied using the CLARA–PRISMA setup. Angular distributions for pure elastic scattering and total cross-sections of the most relevant transfer channels have been measured. The experimental results are compared with predictions from a semiclassical model, showing good agreement for the presently analyzed few neutrons transfer channels. The decay of the most intense reaction products has also been studied, giving indications of the population of states with very short lifetimes.Gadea Raga, Andrés, [email protected]

Isospin character of low-lying states in 56Fe.

Low-lying states in {sup 56}Fe, up to an excitation energy of about 4 MeV, have been investigated by means of inelastic proton and deuteron scattering experiments at {ital E}{sub {ital p}}=65 and 400 MeV and at {ital E}{sub {ital d}}=56 MeV, respectively. Measured cross sections and analyzing powers have been compared with coupled-channels calculations using collective form factors; calculations in both the Schr{umlt o}dinger and Dirac formalisms have been carried out for the proton data. For each probe, the matrix elements have been deduced for transitions from the ground state and from the 2{sub 1}{sup +} state to six quadrupole (2{sup +}) states to one octupole (3{sub 1}{sup {minus}}) and two hexadecapole (4{sub 1}{sup +} and 4{sub 2}{sup +}) states. The obtained matrix elements and the previous values from {gamma} decay or electron inelastic scattering have been used to evaluate the isospin character of the transitions. To discuss the quadrupole mixed-symmetry states in {sup 56}Fe, the deduced neutron ({ital M}{sub {ital n}}) and proton ({ital M}{sub {ital p}}) components of the matrix elements, or equivalently the isoscalar ({ital M}{sub {ital s}}) and isovector ({ital M}{sub {ital v}}) parts, have been compared with theoretical calculations based on the neutron-proton interacting bosonmore » model and on the shell model evaluated in a full {ital f}-{ital p} configuration space. {copyright} {ital 1996 The American Physical Society.}« les