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Reference : UMR7178-REGSOM-074
Workplace : STRASBOURG
Date of publication : Monday, March 22, 2021
Type of Contract : FTC Scientist
Contract Period : 24 months
Expected date of employment : 1 September 2021
Proportion of work : Full time
Remuneration : Between 2675,27 and 3085,92 euros gross per month according to experience
Desired level of education : PhD
Experience required : Indifferent
The research project of this post doctorate concerns 2 instrumental/experimental aspects of the host team's research activities:
- Participate in the preparation of experiments at the new SPIRAL2/NFS facility planned for 2023. The candidate will be in charge of the preparation of the first test at NFS which will have to confirm the feasibility of the measurements (n,xn ) with this neutron beam (beam time expected in autumn). A positive result will enable him/her to draw up a proposal for an experiment that he/she will submit to the PAC GANIL.
- Participate in the instrumental development of the DELCO system at JRC-GELINA (Geel, Belgium). The aim will be to carry out tests of silicon detectors in the framework of the measurement of 238U(n,n') reactions. A proposal of experiment could be written in case of positive test with the current system, otherwise proposals for improvement will be considered.
- the realization of tests and their analysis,
- the preparation of experience,
- writing proposals for experiments to be submitted to the PAC for the facilities involved,
- instrumental development and optimization of electron detection systems,
- writing articles and presenting the results obtained in workshops and conferences in the field.
- An excellent Master's degree (or equivalent) and a PhD completed (< 2 years) (or in the process of completion) in nuclear physics.
- An experience in semiconductor detection systems (Germanium and Silicon Detector) and the analysis of the data recorded with these devices.
- An experience in nuclear structure would be an added asset for the successful completion of the research project.
- Have good oral and written communication skills in English, suitable for preparing scientific publications in world-renowned journals and presenting research at international conferences.
Keywords: nuclear data for energy, cross-section measurements, instrumentation, semiconductor detector, prompt-gamma spectroscopy, conversion electron, silicon detector, data analysis, EC/JRC/GELINA, GANIL/NFS
The activities of the Nuclear Data for Reactors (DNR) Group are part of the nuclear data measurements applied to the reactors of the future. The precise study and optimization of the potential of these new systems and fuel cycles requires a higher level of quality in the evaluated nuclear databases used for simulations. This improvement requires joint work on the experimental and theoretical aspects of the nuclear processes involved in a reactor. One of the challenges is to significantly reduce the uncertainties associated with new experimental data. In this context, our team has focused its efforts on improving knowledge of the (n,xn) process. To do this, we use the method of prompt gamma spectroscopy associated with the time-of-flight technique that allows us to measure the reaction cross sections (n,xn ). By combining the result of these measurements with the predictions of theoretical models to fill in the missing information, we deduce the (n,xn) cross sections .
Our program of measurements concern more particularly reactions involving actinides. Up to now, experiments have been conducted with the "white" neutron beam of GELINA (EC-JRC in Geel, Belgium) where we have developed the GRAPhEME setup, consisting of a set of planar HPGe detectors and a fission chamber. Particular attention has been paid to minimize all sources of uncertainty related to our measuring instruments and the environment. The GELINA facility delivers a neutron beam whose energy range is well adapted to the study of neutron inelastic scattering reactions - (n,n'). With the arrival of GANIL's new SPIRAL2/NFS (Neutrons For Sciences) facility , a new field of investigation becomes possible. Indeed, the neutrons delivered by this facility allow the study of higher threshold processes such as (n,2n) and (n,3n) reactions. The DNR team, in collaboration with EC-JRC Geel and IFIN-HH Bucharest, proposes to carry out measurement campaigns of the (n,2n) and (n,3n) cross section on actinides using the method of prompt gamma spectroscopy. The method, proven for the study of (n,n') reactions at GELINA, can be adapted to NFS. The collaboration has already obtained beam time in 2021 to verify the experimental conditions of the new facility. In addition, we are developing the DELCO (Detector of ELectron of COnversion) detection system, consisting of silicon counters, at JRC-GELINA dedicated to the measurement of conversion electrons emitted during inelastic neutron scattering on the 238U and coming from the de-excitation of low excitation energy levels (a few tens of keV). Indeed, these states decrease mainly by electronic means and the method of prompt gamma spectroscopy then becomes much less precise. The measurement of the emitted conversion electrons would make it possible to complete the information collected via gamma de-excitation with GRAPhEME and thus gain in precision for these transitions of primary importance. During the two years of the contract, several opportunities to present the candidate's work will be offered, notably during workshops or conferences in our field but also at JEFF meetings which take place twice a year. The team also undertakes to help the candidate in his or her search for employment in academic positions (CNRS competition, university ...) following his or her contract.
2. M. Kerveno et al. European Physical Journal A, EDP Sciences, 2015, 51 (12), pp.167.
3. M.Kerveno et al., EPJ Web of Conferences 239, 01023 (2020)
Constraints and risks
Short trips are to be expected in France and abroad (Belgium) for the realization of the experiments.
Experience required: nuclear instrumentation (an experience in nuclear structure would also be welcome)
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