Investigation of Nuclear Reactions at Low Energies on Highly Enriched Isotopes

Abstract

A century has been elapsed since the first observation of nuclear reaction by Rutherford in 1919. Since that time, a lot of efforts were done to comprehend the observed results. Because of the complexity of nuclei as a quantum mechanical objects, complete description of their properties is beyond the present day capabilities of nuclear theory, not only the number of nucleons in a nucleus is large but also because of our inadequate knowledge of the nuclear Hamiltonian itself.

Various tools could be utilized to investigate nuclear reactions. Particle irradiation. in addition to a, /3 and/or 1detection systems, is an example. The accumulated knowledge about nuclei, their behavior and structure forms what is denoted as nuclear data. Precise nuclear data is important and necessary from scientific and practical viewpoint. The most obvious application of nuclear data is the needed in the field of nuclear energy. In addition. the use of radioactive isotopes for medical diagnosis and treatment is a growing industry, where variety of isotopes spread over the periodic table are utilized.

While several isotopes are produced in nuclear reactors through neutron capture and fission, others are preferably produced with accelerated charged particle beams in the low and intermediate energy range. Novel techniques are also used, where an intense neutron source is created with a proton beam interacting with rich neutron target. Low energy nuclear reactions is the dominant reaction in universe, nearly all reaction inside stars occurs at energies below few MeV's. Studying of low energy reaction is possible with high degree of accuracy.

Since the available experimental data is often inadequate in scope to enable direct gen­ eration of continuous evaluated quantities such a.s excitation functions, even through the application of statistical evaluation procedures, extensive use is made of nuclear models to generate the necessary information. Gaps in existing experimental data are supplemented by these calculations (interpolation) and the models are frequently used to provide numerical results in domains where no experimental data are available (extrapolation). Consequently, considerable responsibility is placed upon evaluators to employ models that are reliable for the intended purpose, and to utilize parameters for these models which have been demon­ strated to give reasonable results, i.e. model parameters validated by experimental data. Compilations of recommended nuclear model parameters have been produced and made available for use in such calculations. However, libraries of suggested nuclear model param-