Deexcitation Modes in Spallation Nuclear Reactions

• Published in: Brazilian journal of physics 2016-08, Vol.46 (4), p.415-423
• Main Authors: Velasco, F. G., Guzmán, F., Rodriguez, O., Tumbarell, O., Souza, D. A., Samana, A. R., Andrade-II, E., Bernal Castillo, J. L., Deppman, A.
• Format: Article
• Language: English
• Subjects: General and Applied Physics; Physics; Physics and Astronomy
• ISSN: 0103-9733; 1678-4448
• DOI: 10.1007/s13538-016-0430-7

Spallation nuclear reactions in the range of 0.2 to 1.2 GeV are studied using the CRISP code. A new approach for the deexcitation stage of the compound nucleus was introduced. For the calculations of the level densities, this approach is based on the Back-shifted Fermi gas model (BSFG), which takes into account pairing effects and shell corrections, whereas the calculation of the fission barriers were performed by means of the Extended Thomas-Fermi plus Strutinsky Integral (ETFSI) method, which is a high-speed approximation to the Hartree-Fock method with pairing correlations treated as in the usual BCS plus blocking approach. This procedure is more appropriate to calculate level densities for exotic nuclei. Satisfactory results were obtained and compared with experimental data obtained in the GSI experiments. As another important result, we highlight some directions for the development of a qualitatively superior version of the CRISP code with the implementation of more realistic and suitable physical models to be applied in stable and exotic nuclei that participate in the process. This new version of the code includes several substantial changes in the decay of the hot compound nucleus which allow satisfactory agreement with the experimental data and a reduction of the adjustment parameters.