The energy spectra of protons and light nuclei produced by the interaction of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ projectiles with Al and U targets have been investigated at incident energies ranging from 0.25 to 2.1 GeV per nucleon. Single fragment inclusive spectra have been obtained at angles 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 from ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ bombardment of uranium. 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 spectra 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.

NUCLEAR REACTIONS $\mathrm{U}({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne},X)$, $E=250\mathrm{}$ MeV/nucl.; $U({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne},X)$, $U(\alpha ,X)$ $E=400\mathrm{}$ MeV/nucl.; $\mathrm{U}({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne},X)$, $\mathrm{Al}({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne},X)$, $E=2.1\mathrm{}$ GeV/nucl.; measured $\sigma (E,\theta )$, $X=p,d,t,{}_{}{}^3{}_{}{}^{}\mathrm{He},{}_{}{}^4{}_{}{}^{}\mathrm{He}$. $\mathrm{U}({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne},X)$, $U(\alpha ,X)$, $E=400\mathrm{}$ MeV/nucl.; $U({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne},X)$, $E=2.1\mathrm{}$ GeV/nucl.; measured $\sigma (E,\theta )$, Li to O. $\mathrm{U}({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne},X)$, $U({}_{}{}^{12}{}_{}{}^{}\mathrm{C},X)$, $E=2.1\mathrm{}$ GeV/nucl.; measured $\sigma (E,90°)$, ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ to B. Nuclear fireballs, coalescence, thermodynamics of light nuclei production.

• Received 13 May 1977

DOI:https://doi.org/10.1103/PhysRevC.16.629

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Physical Review C 50^th Anniversary Milestones

This collection of milestone papers from PRC highlights research that remains central to current developments in nuclear physics.