High-spin Selection In Compound Nucleus Decay By Detecting Multiple Alpha-chains

A large area hodoscope for the detection of light charged particles has been built by using silicon strip detectors and CsI(Tl) scintillators with photodiode readout. Details of the hodoscope construction, tests and operation are reported. Results obtained in selecting high spin states in the decay of medium-light compound nuclei by multiple alpha detection are shown. The possibilities and limitations of this technique are discussed

Alpha-particle Emission As A Probe of the Level Density In Highly Excited A-similar-to-200 Nuclei

The alpha particle emission from 90 to 140 MeV F-19+Ta-181 fusion-evaporation reactions has been studied. The comparisons of the experimental spectral shapes and multiplicities with statistical model predictions indicate a need to use an excitation energy dependent level-density parameter a = A/K in which K increases with excitation energy. This increase is more rapid than that in lower mass nuclei. The effect of this change in level. density on the prescission multiplicities in fission is significant

Heart failure in Eastern Veneto: prevalence, hospitalization rate, adherence to guidelines and social costs

Heart failure is a preminent problem of public health, requiring innovating methods of health services organization. Nevertheless, data are still not available on prevalence, hospitalization rate, adherence to Guidelines and social costs in the general Italian population. The necessity to identifying patients with heart failure derives from the efficacy of new therapeutic interventions in reducing morbidity and mortality. In this study we aimed to identify, in a subset of the Eastern Veneto population, patients with heart failure through a pharmacologic-epidemiologic survey. The study was divided in 5 phases: 1) identification of patients on furosemide in the year 2000 in the ASL 10 of Eastern Veneto general population, through an analysis of a specific pharmaceutic service database; 2) definition of the actual prevalence of heart failure in a casual sample of these patients, through data base belonging to general practitioners, cardiologists, or others. Diagnosis was based on the following criteria: a) previous diagnosis of heart failure; b) previous hospitalization for heart failure; c) clinical evidence, with echocardiographic control in unclear cases; 3) survey of hospitalizations; 4) evaluation of adhesion to guidelines, through both databases and questionnaires; 5) analysis of the social costs of the disease, with a retrospective “bottom up” approach. From a total population of 198.000 subjects, we identyfied 4502 patients on furosemide. In a casual sample of 10.661 subjects we defined a prevalence of heart failure in Eastern Veneto of 1.1%, that rised to 7.1% in octuagenarians. The prescription of life saving drugs was satisfactory, while rather poor was the indication to echocardiography and to cardiologic consultation. Hospitalization rate for DRG 127 was low: 2.1/1000 inhabitants/year in the general polulation and 12.5 /1000 inhabitants/year in patients >70 years of age. Yearly mortality was 10.3%. Social costs were elevated (15.394 €/patient/year), due to a relevant sanitary component (hospital 53%, drugs 28%) and particularly a to an indirect cost component. In conclusion, the assumption of furosemide lends itself as a good marker for identifying patients with heart failure. Patient identification is simple, cheap and cost-efficient, and can be easily reproduced in other regional areas

Fission dynamics and fast fission: case study of an intermediate mass system

Light charged particles in coincidence with evaporation residues and heavy fragments have been measured for the 200MeV S-32 + Mo-100 reaction leading to the Ce-132 composite. The alpha pre-scission multiplicities are remarkably larger than what found in the same system at 240 MeV. This unexpected trend can be ascribed to the opening of the fast fission channel at 240 MeV. The statistical model reproduces the light charged particles pre-scission multiplicities at 200 MeV if a delay time of tau(d) approximate to 26 x 10(-21)s is considered

Fission dynamics with the 4 pi detector 8 pi LP

A 4pi light charged particle spectrometer, named 8piLP, is in operation at the Laboratori Nazionali di Legnaro (Italy) for the study of the reaction mechanisms produced in low-energy heavy-ion reactions. The spectrometer has recently been used in a study of fission dynamics that involves the detection of light charged particles in the fission and evaporation residue channel in a system of intermediate fissility, as well as in a study of multinucleon transfer to heavy target. Data on the system 240 MeV S-32 + Mo-100 are presented. Dynamical effects extracted as a consequence of the comparison of the data to the statistical model calculations are discussed

Neutron-spectra From the Er-156 Compound Nucleus Populated By C-12-induced and 64ni-induced Reactions

Inclusive neutron spectra from the decay of Er-156 compound nucleus populated at E(x)=47 MeV excitation energy by the C-12+Sm-144 and Ni-64+Zr-92 reactions have been measured. The neutron spectra from the Ni-64-induced reaction are strongly contaminated by other reactions different from fusion evaporation so that inclusive spectra cannot be used to test nonstatistical or entrance channel effects in the compound nucleus decay

The 8pLP Project: a 4pi Light Charged Particle Detection Array at LNL

A 4 pi detection system sensitive to light charged particles is being developed at the Laboratori Nazionali di Legnaro (LNL) for the study of the reaction mechanisms produced in heavy ion collisions at energies up to 20 AMeV. The 8 pi LP apparatus is a telescope assembly characterized by large solid angle (90% of 4 pi) and high granularity (262 modules). Particle identification at low energy is obtained by combining Delta E-E, TOF and PSD techniques. Each telescope is made of a 300 mu m passivated silicon detector and a 15 mm (or 5 mm) CsI(TI) crystal with photodiode readout. Thresholds for particle identification range from 1 MeV for protons and 3 MeV for alpha particles to about 2-3 AMeV for C ions. A low-cost trigger and readout bus system has been developed to cope with the large number of parameters and the high counting rate. The system will be fully operational for experiments in the Summer of 1997

Breakup processes of 6,7Li projectiles from a 208Pb target at Coulomb barrier energies

Large \u3b1 production cross sections were measured for the systems 6,7Li+208Pb; they were identified with the total breakup cross sections. A theoretical description based on coupled channels method, also including coupling to a discretized continuum, underestimates the experimental data. These large cross sections, also found for the systems 6He,9Be+209Bi, originate from the low binding energies of these light nuclei. The total reaction cross sections for these systems, deduced from the elastic scattering, coincide with the fusion + breakup ones

Inclusive and exclusive measurements of high energy gamma-rays in the 101 MeV 19F + 181Ta fusion reaction

The high energy gamma-rays from the fusion-evaporation reaction 101 MeV F-19 + Ta-181 have been measured in coincidence with different gamma-ray fold windows or discrete gamma-rays in final residual nuclei. The line-shape Analysis of the high energy gamma-ray spectra confirms the large deformation of the Pb-200 nuclei at high angular momenta. Coincidences with discrete gamma-transitions evidence a strong correlation between gamma-rays in the Giant Dipole Resonance region (E-gamma greater than or equal to 8 MeV) and final evaporation residues