（N-Z） Odd-Even Effect for the Non-Equilibrium Mechanism of （p, n） Reactions

作     者：Nikolay V. Komilov 

作者机构：Unemployed 9 Bolleana PI Athens 45701 USA 

出 版 物：《Journal of Physical Science and Application》 (物理科学与应用（英文版）)

年 卷 期：2014年第4卷第3期

页      面：166-176页

学科分类：081704[工学-应用化学] 08[工学] 0817[工学-化学工程与技术] 0827[工学-核科学与技术] 082701[工学-核能科学与工程] 081701[工学-化学工程] 

主　　题：Nuclear reactions neutron emission direct mechanism odd-even effect. 

摘      要：The neutron spectra and angular distributions from （p,n） reactions in the input proton energy range 6-25 MeV were analyzed. These are the old experimental data, however, re-analysis of these data reveals very interesting peculiarities which never have been discussed before. The high energetic part of neutron spectrum due to the direct mechanism changes considerably from one isotope to other. This difference was described with incorporation of two components which provide the ＂broad bump＂, or ＂step like＂ shape of neutron spectra at high energy. The properties of these components are： different shape, energy shift between them, and very strong fluctuation between different isotopes for ratio of cross sections connected with partial contribution. One may conclude that shape of non-compound neutron spectrum demonstrates very strong （N-Z） odd-even effect. The direct comparison of experimental data, and semi-empirical results with （p,n） spectra predicted by the EMPIRE code, gave evidence that the traditional approach cannot predict this effect. New finding may explain the ＂constant temperature＂ dependence for level density in mass range A-60 discussed in several investigations. These new experimental peculiarities were demonstrated, and it may be considered as reality. At the same time there is not consequent physical model for their explanation. The fact that spectrum shape is correlated with N-Z value may give a hint that discussed effects are connected with ＂halo-neutrons＂.