Pre-Equilibrium Processes in Nuclear Reactions

Theoretical description of the experimentally obtained spectra for protons and α-particles and model calculations for the neutron spectra in the reactions with heavy ions has been presented. The hybrid model of non-equilibrium processes was used. Equilibrium evaporation process was analyzed in the framework of the statistical theory of nuclear reactions with Monte-Carlo simulation including certain dynamical and kinematical characteristics. This approach was included in PACE code, which permits to simulate Monte-Carlo de-excitation nuclear process. The Fermi-gas model and level-density phenomenological model for the variation of the nuclear level density parameters was used. In this approach data on 16 O +116 Sn reaction with Ebeam = 130, 250 MeV were analyzed. Double-differential light charged particle spectra for this reaction were measured using the GARFIELD apparatus in coincidence with evaporation residues. The experimental data were collected in four angular ranges from 29 to 41, 41 to 53, 53 to 67 and 67 to 82 degrees in the laboratory system. The results of the calculations are shown and discussed for these four angular ranges. The contributions from the evaporative and pre-equilibrium processes were analyzed in connection with different nucleus equilibration mechanisms.

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Pre-equilibrium processes in nuclear reactions

Heavy-Ion Collisions - Lecture Notes in Physics ◽

10.1007/bfb0018099 ◽

1982 ◽

pp. 220-247 ◽

Cited By ~ 2

Author(s):

P. E. Hodgson

Keyword(s):

Nuclear Reactions ◽

Equilibrium Processes

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Pre-equilibrium processes in nuclear reactions

Nature ◽

10.1038/292671a0 ◽

1981 ◽

Vol 292 (5825) ◽

pp. 671-672 ◽

Cited By ~ 2

Author(s):

P.E. Hodgson

Keyword(s):

Nuclear Reactions ◽

Equilibrium Processes

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Pre-equilibrium processes in nuclear reactions

Radiation Effects ◽

10.1080/00337578608208667 ◽

1986 ◽

Vol 95 (1-4) ◽

pp. 27-46 ◽

Cited By ~ 3

Author(s):

P. E. Hodgson ◽

G. M. Field ◽

H. Gruppelaar ◽

P. Nagel

Keyword(s):

Nuclear Reactions ◽

Equilibrium Processes

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Nuclear Processes Related to the Ap Stars and the Heaviest Chemical Elements

International Astronomical Union Colloquium ◽

10.1017/s0252921100080520 ◽

1976 ◽

Vol 32 ◽

pp. 169-182

Author(s):

B. Kuchowicz

Keyword(s):

Nuclear Physics ◽

Nuclear Reactions ◽

Chemical Elements ◽

Fission Products ◽

Abundance Pattern ◽

Isotopic Shifts ◽

Processed Material ◽

R Process ◽

Ap Stars ◽

Nuclear Processes

SummaryIsotopic shifts in the lines of the heavy elements in Ap stars, and the characteristic abundance pattern of these elements point to the fact that we are observing mainly the products of rapid neutron capture. The peculiar A stars may be treated as the show windows for the products of a recent r-process in their neighbourhood. This process can be located either in Supernovae exploding in a binary system in which the present Ap stars were secondaries, or in Supernovae exploding in young clusters. Secondary processes, e.g. spontaneous fission or nuclear reactions with highly abundant fission products, may occur further with the r-processed material in the surface of the Ap stars. The role of these stars to the theory of nucleosynthesis and to nuclear physics is emphasized.

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Nuclear Reactions in Deuterium Titanium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134260 ◽

1990 ◽

Vol 48 (2) ◽

pp. 134-135

Author(s):

D.M. Vanderwalker

Keyword(s):

Nuclear Reactions ◽

Ion Beam ◽

Exothermic Reaction ◽

Pure Titanium ◽

Fundamental Interest ◽

Transmission Electron ◽

Iodide Titanium ◽

A Cell ◽

After Hours ◽

Quantity Of Heat

There is a fundamental interest in electrochemical fusion of deuterium in palladium and titanium since its supposed discovery by Fleischmann and Pons. Their calorimetric experiments reveal that a large quantity of heat is released by Pd after hours in a cell, suggesting fusion occurs. They cannot explain fusion by force arguments, nor can it be an exothermic reaction on the formation of deuterides because a smaller quantity of heat is released. This study examines reactions of deuterium in titanium.Both iodide titanium and 99% pure titanium samples were encapsulated in vacuum tubes, annealed for 2h at 800 °C. The Ti foils were charged with deuterium in a D2SO4 D2O solution at a potential of .45V with respect to a calomel reference junction. Samples were ion beam thinned for transmission electron microscopy. The TEM was performed on the JEOL 200CX.The structure of D charged titanium is α-Ti with hexagonal and fee deuterides.

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The evolution of the microstructure of 600 Mev proton irradiated materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178148 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1002-1003

Author(s):

R. Gotthardt ◽

A. Horsewell ◽

F. Paschoud ◽

S. Proennecke ◽

M. Victoria

Keyword(s):

Nuclear Reactions ◽

Dislocation Loops ◽

Defect Clusters ◽

Weak Beam ◽

Stacking Fault Tetrahedra ◽

Small Defect ◽

Sufficient Intensity ◽

Reactor Materials ◽

Metallic Impurities ◽

Beam Technique

Fusion reactor materials will be damaged by an intense field of energetic neutrons. There is no neutron source of sufficient intensity at these energies available at present, so the material properties are being correlated with those obtained in irradiation with other irradiation sorces. Irradiation with 600 MeV protons produces both displacement damage and impurities due to nuclear reactions. Helium and hydrogen are produced as gaseous impurities. Other metallic impurities are also created . The main elements of the microstructure observed after irradiation in the PIREX facility, are described in the following paragraphs.A. Defect clusters at low irradiation doses: In specimens irradiated to very low doses (1021-1024 protons.m-2), so that there is no superimposition of contrast, small defect clusters have been observed by the weak beam technique. Detailed analysis of the visible contrast (>0.5 nm diameter) revealed the presence of stacking fault tetrahedra, dislocation loops and a certain number of unidentified clusters . Typical results in Cu and Au are shown in Fig. 1.

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