International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators
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ADS/ND-06 Production of A+1 and Z+1 Isotopes in Proton-Induced Reaction on AZ Nuclei. Application to Po Production in p - 209Bi to Bi Isotopes in p - 208Pb reactions J. Cugnon Unversity of Liège, Liège, Belgium Corresponding Author: cugnon@plasma.theo.phys.ulg.ac.be Most of the isotopes produced in spallation reactions induced by nucleons in the GeV range have a mass and a charge smaller and sometimes sizably smaller than the original mass and charge of the target nucleus, respectively. This is consistent with the current model used to describe these reactions, namely the intranuclear cascade + evaporation model. However, occasionally, the mass of the so-called residue exceeds the target mass number, by one unit. This is possible when the incident nucleon is absorbed and when a non-baryonic particle is emitted. At low energy, the latter could be a photon. But at sufficiently high incident energy, the emitted particle could be a pion. Residues with a charge one unit larger than the target charge can be produced by conventional (p, xn) reactions, except when their mass number exceeds the target mass number by one unit, in which case a (p, π0) process is at work. An interesting experimental study of the Bi isotopes produced in p - 208Pb collisions at 1 GeV has been published by the FRS group at GSI in Ref. [1]. This set of reactions are quite interesting, because they involve the emission of a single pion or of a pion with a very low number of nucleons. Production of residues close to the target thus provides with a good test for the pion dynamics of INC models. We have just recently improved this feature in the Liège INCL4 model [2]. In this paper, we want to apply our modified INCL4 model to this problem. As typical examples, we consider the production Po isotopes in p- 209Bi reactions and Bi isotopes in p - 208Pb reactions. We will indeed show that good agreement with the data can be achieved only when the pion potential is introduced and when the energy-dependance of the nucleon potential is properly taken into account. In particular, this is true for the production of 210Po by p - 209Bi reactions at higher energy when the (p, π0) mechanism replaces the (p, γ) process. This is still true to some extent for the production of 208Po and 209Po isotopes at any energy, since it that case, the photon capture process is negligible. We also arrive at a similar conclusion for the Bi isotope production in p - 208Pb reactions at 1 GeV, after comparison with the data of Ref. [3]. We also investigate the influence of our calculations for the radiotoxicity associated with Pb-Bi targets bombarded by high energy protons. [1] A. Kelic et al., Phys. Rev. C 39 (2004) 064608.
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