Showing papers by "Technische Universität Darmstadt published in 1976"

Nuclear Fireball Model for proton inclusive spectra from relativistic heavy-ion collisions

Abstract: A simple model is proposed for the emission of nucleons with velocities intermediate between those of the target and projectile. In this model, the nucleons which are mutually swept out from the target and projectile form a hot quasiequilibrated fireball which decays as an ideal gas. The overall features of the proton-inclusive spectra from 250- and 400-MeV/nucleon $^{20}\mathrm{Ne}$ ions and 400-MeV/nucleon $^{4}\mathrm{He}$ ions interacting with uranium are fitted without any adjustable parameters.

Final State Interactions in the Production of Hydrogen and Helium Isotopes by Relativistic Heavy Ions on Uranium

Abstract: Double-differential cross sections have been measured for high-energy $p$, $d$, $t$, $^{3}\mathrm{He}$, and $^{4}\mathrm{He}$ particles emitted from uranium targets irradiated with $^{20}\mathrm{Ne}$ ions at energies of 250, 400, and 2100 MeV/nucleon and $^{4}\mathrm{He}$ ions at 400 MeV/nucleon By using the shape and yield of the proton energy spectra, the shape and yield of the $d$, $t$, $^{3}\mathrm{He}$, and $^{4}\mathrm{He}$ energy spectra can be deduced at all measured angles for all incident projectile energies by assuming that they are formed by a coalescence of cascade nucleons, using a model analogous to that of Butler and Pearson, and Schwarzschild and Zupan\ifmmode \check{c}\else \v{c}\fi{}i\ifmmode \check{c}\else \v{c}\fi{}

Fusion and interaction barrier parameters and critical angular momenta from Cl 35 -induced reactions

Abstract: Cross sections for evaporation residue formation and fission following complete fusion of /sup 35/Cl with /sup 27/Al, /sup 48/Ti, /sup 54/,/sup 56/Fe, /sup 58/,/sup 60/,/sup 62/,/sup 64/Ni, /sup 90/Zr, and /sup 116/,/sup 124/Sn have been measured with counter telescopes for laboratory projectile energies between 70 and 170 MeV. Elastic scattering of /sup 35/Cl + /sup 58/,/sup 62/Ni has been measured near the interaction barrier. The excitation functions for complete fusion are analyzed with a semiclassical model, and fusion barrier heights and radii are extracted. These data are discussed in terms of the nuclear density overlap and the nuclear potential contributions to the fusion barrier. The results are compared with the predictions of several heavy ion potential models and with parameters for the interaction deduced from elastic scattering data. For the systems with masses A < 100 about 70% of the total reaction cross section appears as complete fusion. This fraction decreases with increasing mass of the compound system. Evaporation residue and fission excitation functions have been analyzed by the Bohr-Wheeler model using the rotating liquid drop model of Cohen, Plasil, and Swiatecki. To first order these calculations give a satisfactory description of both sets of results. (AIP)

Central collisions of relativistic heavy ions

Abstract: The energy spectra of protons and light nuclei produced by the 0 • 0 f 4 d 20 0 t 0 1 0 th 1 d . h b ~nteract~on o He an Ne pro]ec ~ es w~ A an U targets ave een I investigated at incident energies ranging from 0.25 to 2.1 GeV per nucleon. Single fragment inclusive spectra have been obtained at angles 0 0 . between 25 and 150 , in the energy range from 30 to 150 MeV/nucleon. The multiplicity of intermediate and high energy charged particles was determined in coincidence with the measured fragments. In a separate study, fragment spectra were obtained in the evaporation energy range 12 20 0 from C and Ne bombardment of uran~um. We observe structureless, exponentially decaying spectra throughout the range of studied fragment masses. There is evidence for two major classes of fragments; one with emission at intermediate temperature from a system moving slowly in the lab frame, and the other with high temperature emission from a system propagating at a velocity intermediate between target and projectile. The high energy proton spect_ra are fairly well reproduced by a nuclear fireball model based on simple geometrical, kinematical and statistical assumptions. Light cluster emission is also discussed in the framework of statistical models.