Abstract
α particles were measured in coincidence with projectile-like reaction products (oxygen and carbon) produced in deep-inelastic16O+58Ni collisions at about 6 MeV/N bombarding energy. The kinematic analysis of the HI andα energies measured as a function ofΘ α gives strong evidence for a sequential process: the target-like fragments are excited by the deep-inelastic collision and undergo subsequentα decay. In contrast, the angular correlations show a pronounced forward peak, indicative of direct or pre-equilibriumα emission. The emission time for the latter is estimated to be of the order of 2×10−21 s. To resolve this conflict of co-existing statistical and direct features of the pre-equilibrium emission, the concept of a hot spot is proposed. From the angular correlation and from theα multiplicities, a local temperature ofT−3.5 MeV is deduced which agrees well with the temperature derived from the shape of theα spectra. The spot size is estimated to be 1/5 of the sphere.
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We gratefully acknowledge the collaboration during the early stages of the experiment, with Ch. Bercks, F.-J. Demond, G. Rudolf and Prof. J.D. Fox. Among the many colleagues we had critical and fruitful discussions with, we are especially indebted to Prof. H.A. Weidenmüller and the referee of our paper.
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Ho, H., Albrecht, R., Dünnweber, W. et al. Pre-equilibrium alpha emission accompanying deep-inelastic16O+58Ni collisions. Z Physik A 283, 235–245 (1977). https://doi.org/10.1007/BF01407203
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DOI: https://doi.org/10.1007/BF01407203