Role of breakup processes in deuteron-induced spallation reactions at 100-200 MeV/nucleon

Background: Use of deuteron-induced spallation reactions at intermediate energies was recently proposed for transmutation of several long-lived fission products (LLFPs). In the design study of a transmutation system using a deuteron primary beam, accurate cross section data of deuteron-induced reactions on the LLFPs are indispensable. Reliable model predictions play an important role in completing the necessary cross section data since currently available experimental data are very limited. Under the circumstances, we have been developing a code system dedicated for deuteron-induced reactions, which is called DEURACS. Purpose: Aiming to predict the production cross sections of residual nuclei, the purpose of the present work is to clarify the role of deuteron breakup processes in deuteron-induced spallation reactions at intermediate energies. Methods: Isotopic production cross sections of residual nuclei in the deuteron-induced reactions on Zr-93 and Pd-107 at 100-200 MeV/nucleon are analyzed using DEURACS, in which the breakup processes are explicitly taken into account. The calculated cross sections are decomposed into individual components corresponding to the absorption of either neutron or proton in the incident deuteron, or the deuteron itself. Results: The calculated cross sections reproduced the experimental data well over a wide mass number range of residual nuclei. From a component-by-component analysis, it was found that the components of nucleon absorption make the significant contributions to the production of residual nuclei. Conclusions: Consideration of the breakup processes is essential to predict the production cross sections of residual nuclei in deuteron-induced reactions. The framework of DEURACS is applicable to deuteron-induced spallation reactions at intermediate energies.