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@opreacristiana • 4 years ago
Short Report
Prof. Cristiana Oprea
Project Leader, Senior Experimentalist in Nuclear Physics
Frank Laboratory for Neutrons Physics
Department of of Experimental Nuclear Physics with Neutrons
Theme from JINR Dubna 2018 Topical Plan: 03-4-1128-2017/2019 Investigation of Neutron Nuclear Interactions and Properties of the Neutron

A. Fundamental Researches
1. Nuclear Fission
Neutron-induced fission and photofission processes on 233U, 238U and other isotope nuclei were investigated. Variables of interest in nuclear fission have been determined such as effective sections, mass distributions, prompt neutron distribution, isotope production, isomeric ratios, etc. The effective sections were evaluated by applying the statistical formalism of nuclear reactions using its own programs and the Talys software package (a code system dedicated to the calculation of effective sections and the structure of the nucleus). The corresponding description of the fission experimental sections in the processes 233U (n, f), 238U (n, f), 238U (gamma, f) for fast neutrons with energies starting from the neutron threshold up to 25 MeV allowed the evaluation of the mass distributions of fission fragments before and after neutron emission, prompt neutron emission, isotope production applying the Brosa formalism. The theoretical evaluations were performed in a wide range of incident energies that are in good agreement with the experimental data of mass distribution and dependence of prompt neutrons (depending on the energy or mass of fission fragments) for only a few incident energies.
In the case of photofission of the 238U nucleus, the isomeric ratios were applied applying the Huizenga formalism, considering different types of braking radiation sources, for Xe, Sb and I isotopes. The experimental values, obtained at the Flerov Laboratory for Nuclear Reactions at the MT25 Microtron, are in relatively good concordance with the theoretical evaluations. Isomeric reports are of interest in fundamental nuclear physics problems because they provide data on the distribution of spines as well as from the application point of view for the production of isotopes.

2. Symmetry Breaking in Nuclear Reactions Induced By Slow Neutrons

New approach for extraction of weak non leptonic matrix element from the analysis of experimental and theoretical data of asymmetry and spatial parity violation effects in neutrons induced reactions with emission of gamma quanta, charged particles and scattering process on medium and heavy nuclei lile 35Cl, 14N, 204Pb. (A. Oprea & C. Oprea)
Oral Presentations
1. Annual Session of Faculty of Physics, 21 June 2013, Bucharest - Magurele
2. XXI International Seminar of Interaction of Neutrons with Nuclei, 20-25 May 2013, Dubna, Russian Federation
2014 FLNP First Prize on Scientific Reports
1. Yu. M. Gledenov, P.V. Sedyshev, M. V. Sedysheva, V. Vesna, A. Oprea, C. Oprea
Romanian Reports (2015)
2. One article in preparation (2018)

3. Nuclear Reactions Induced by Fast Neutrons

Non statistical effects (Gledenov et all) discovered in nuclear reactions induced by fast neutrons with emission of charged particles like 147Sm(n,)144Nd and explained qualitatively by cluster emission in even-even compound nuclei based on channel radius changing (A. Oprea & C. Oprea).
Oral Presentations
1. XXVI International Seminar of Interaction of Neutrons with Nuclei, 2018 May 28 – June 1, Xi’an China
2. XIIIth International Conference on Nuclear Reaction Mechanism, 11-15 June, Varenna Italy
3. Annual Session of Faculty of Physics, 21-22 June 2018 Bucharest - Magurele
One article submitted for publication (2018)

B. Applicative Researches

1. Photonuclear Reactions for Isotopes Production for Applications

Method for evaluation of production of isotopes and isomer of interest in applications in fission induced by neutrons and gamma quanta based on Huizenga approach and Talys codes.
1. European Nuclear Physics Conference (EUNPC), 2-7 September 2018, Bologna, Italy
2. International Workshop on Nuclear Data Evaluation for Reactor Applications, 8-12 October 2018, Aix en Provence, France
2 articles in preparations

2. Atomic and Nuclear Analytical Methods in the Analysis of Cosmic Meteorites

Meteorites samples from South Africa furnished by Faculty of Physics, University of Bucharest were analyzed for the first time using atomic and nuclear analytical methods. Measurements were realized at Faculty of Physics, CETAL from Bucharest Magurele and at basic facilities of FLNP JINR Dubna. The investigations are of a certain interest in astrophysics.
Oral Presentations
1. Annual Session of Faculty of Physics, 23-24 June 2017, Bucharest - Magurele
2. XXV International Seminar of Interaction of Neutrons with Nuclei (ISINN25), 22-26 May 2017, Dubna, Russian Federation
One article in preparation

C. Importance

The results of the present projects are in well accordance with the National Plan for Developing and Innovation of Romania for the period 2015 – 2020, paragraph 4.4. “Frontiers Advanced Fundamental Researches” on the direction (pylon) Extreme Light Infrastructure – Nuclear Physics and they represents novelty as research direction in Romania.
The present investigations give the possibility to know new modern theoretical approaches in the field of neutrons induced reactions and fission processes as well as to have access at performing JINR Dubna basic facilities, new experimental techniques and methods related to modern nuclear data which can be used in nuclear technologies, medicine, electronics, material sciences.



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