Charged-particle spectra: 80 MeV deuterons on Al27 and Ni58 and 70 MeV deuterons on Zr90, Pb208, and Th232

J. R. Wu, C. C. Chang, and H. D. Holmgren
Phys. Rev. C 19, 370 – Published 1 February 1979
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Abstract

Complete energy spectra and angular distributions of charged light particles (Z2 and A4) were measured for the bombardment of 80 MeV deuterons on Al27 and Ni58 and 70 MeV deuterons on Zr90, Pb208, and Th232. The charged particles were detected by two triple-counter telescopes using combinations of ΔEE and time-of-flight techniques for particle identification. The experimental results are presented in cross sections doubly differential in energy and angle, as well as in angle- and energy-integrated cross sections. For all the nuclei studied, the proton energy spectra show large deuteron-breakup peaks centered at approximately half of the incident deuteron energy at forward angles. The energy spectra for the same type of emitted particle are similar in shape for all nuclei at a given angle except in the region of the low-energy evaporation peak. The magnitude of evaporation peak varies rapidly with target mass. The total nonequilibrium yield of charged light particles is approximately (300±50)A13 mb. The angular distributions for the high-energy particles are strongly forward peaked and are nearly isotropic for the low-energy particles. The deuteron and triton yields increase with A; while those for p, He3, and α particles decrease with A. The total charged light-particle yield is found to be roughly two times the total reaction cross section (σR) for light- and medium-mass nuclei; while it is less than σR for heavy nuclei. The experimental results were analyzed within the framework of the pre-equilibrium exciton model together with evaporation theory. The pre-equilibrium exciton model using a 3p-1h initial configuration reproduces the experimental angle-integrated energy spectra for all target nuclei studied both in spectral shapes and in magnitudes for all emitted particles except protons. The deuteron-breakup yield in the proton spectra was compared with the Serber model. When the breakup yield is added to the pre-equilibrium yield, agreement is obtained for the proton spectra.

NUCLEAR REACTIONS Al27, Ni58, Zr90, Pb208, Th232 (d,xp), (d,xd), (d, xt), (d, xHe3), (d,xα), E=80, 70 MeV θ=20°150°, measured d2σdΩdε, deduced dσdε and σ(E). Comparisons with pre-equilibrium exciton, compound nuclear evaporation and deuteron-breakup models.

  • Received 1 February 1978

DOI:https://doi.org/10.1103/PhysRevC.19.370

©1979 American Physical Society

Authors & Affiliations

J. R. Wu, C. C. Chang, and H. D. Holmgren

  • Department of Physics and Astronomy, University of Maryland, College Park, Maryland 20742

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Issue

Vol. 19, Iss. 2 — February 1979

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