Dissertations / Theses on the topic 'Spectrométrie neutron'
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Mayet, Pascale. "Isomers populated by projectile fragmentation in the neutron-rich A=180-200 mass region." Université Louis Pasteur (Strasbourg) (1971-2008), 2001. http://www.theses.fr/2001STR13131.
Combe, Rodolphe. "Développement d'un télescope à protons de recul pour la spectrométrie neutron : applications à l'instrumentation de précision et à la protonthérapie." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAE015/document.
Neutrons are studied in various domains as, for example, particles of interest in fundamental physics, tool in biology and elemental analysis, or danger for human in radioprotection. The measurement of the neutron energy is necessary in all these domains, but the characteristics of the spectrometers can vary greatly from an application to another. In the field of this thesis, we conceived a recoil proton telescope using ultra-fast CMOS pixels sensors. This compact detector allows a real-time reconstruction of the neutron spectrum up to very high flux. The applications developed during this thesis are precision measurement at the AMANDE accelerator between 4 and 20 MeV, as part of a collaboration with IRSN-Cadarache, and the characterization of secondary neutrons produced in protontherapy treatment rooms
Denise, Bertrand. "Etude par spectrométrie neutronique de la phase à désordre d'orientation du néopentane et du perchlorate de potassium." Paris 6, 1986. http://www.theses.fr/1986PA066342.
Mougeot, Maxime. "Nuclear Collectivity Studied through High Precision Mass Measurements of Neutron-rich Argon and Chromium Isotopes." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS455/document.
Due to their inherent relationship with the binding energy, nuclear masses are the fingerprint of all the interactions taking place within the nucleus. As such, precise and accurate mass values are an essential ingredient to the comprehensive understanding of nuclear phenomena in exotic regions of the chart of nuclides. In this thesis, two key regions exhibiting dramatic structural evolution are investigated by means of high precision mass measurements performed with the online mass spectrometer ISOLTRAP at ISOLDE/CERN. Numerous spectroscopy results indicate that the chromium isotopic chain exhibits the most dramatic structural changes within the region situated south of 68Ni. This thesis reports on the first high-precision mass measurements of the neutron-rich 58-63Cr isotopes using the well established Penning trap mass spectrometry technique as well as the MRToF-MS technique pioneered at ISOLTRAP in recent years. The obtained mass values are up to 300 times more precise than the ones currently available in the literature. At odds with previous results, the new mass values exclude a sudden onset of ground-state collectivity rather favouring a smooth transition towards deformation approaching N=40. The question of the persistence of the N=28 shell closure in the Argon chain is also studied in this PhD work through the measurement of the neutron-rich 46-48Ar isotopes. The results of improved precision confirm the presence of a strong N=28 shell closure in the Argon chain. For both datasets, the detailed data analysis procedure will be presented. The implication of the obtained mass values for nuclear structure will be discussed through a phenomenological discussion of the binding energy trend. The results will also be discussed in the light of state of the art nuclear models including results from the promising valence-space formulation of the ab-initio IM-SRG formalism
Diez, Bénédicte. "Détermination de la composition des surfaces planétaires par spectroscopie gamma et neutron." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/554/.
Measuring the neutron and gamma ray fluxes produced by the interaction of galactic cosmic rays with planetary surfaces allow constraining the chemical composition of the upper tens of centimeters of material. Two different angles are proposed to study neutron and gamma spectroscopy: data processing and data interpretation. The present work is in line with two experiments, the Mars Odyssey Neutron Spectrometer and the Selene Gamma Ray Spectrometer. A review of the processing operations applied to the MONS dataset is proposed. The resulting dataset is used to determine the depth of the hydrogen deposits below the Martian surface. In water depleted regions, neutron data allow constraining the concentration in elements likely to interact with neutrons. The confrontation of these results to those issued from the Gamma Ray Spectrometer onboard Mars Odyssey provides interesting insight on the geologic context of the Central Elysium Planitia region. These martian questions are followed by the study of the Selene gamma ray data. Although only preliminary processing has been done to date, qualitative lunar maps of major elements (Fe, Ca, Si, Ti, Mg, K, Th, U) have already been realized
Serre, Sébastien. "Définition par modélisation, optimisation et caractérisation d’un système de spectrométrie de neutron par sphères de Bonner étendu au domaine des hautes énergies." Aix-Marseille 3, 2010. https://tel.archives-ouvertes.fr/tel-00630202.
Traore, Issiaka. "Etude et caractérisation des fonctions de réponse des détecteurs solides de traces nucléaires : applications à la dosimétrie radon et neutron." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01067060.
Serre, Sébastien. "Définition par Modélisation, Optimisation et Caractérisation d'un Système de Spectrométrie de Neutron par Sphères de Bonner Etendu au Domaine des Hautes Energies." Phd thesis, Université Paul Cézanne - Aix-Marseille III, 2010. http://tel.archives-ouvertes.fr/tel-00630202.
Loche, Florence. "Contrôle des déchets radioactifs et couplage de mesures neutron/gamma : exploitation de la capture radiative pour corriger les effets de matrice pénalisant la mesure de la masse fissile par interrogation neutronique active." Grenoble INPG, 2006. http://www.theses.fr/2006INPG0116.
Ln the framework of radioactive waste drums control, difficulties arise in the non-destructive measurement of fissile mass 235U, 239PU. . . ) by Active Neutron Interrogation (ANI), when dealing with matrices containing materials (CI, H. . . ) influencing the neutron flux. The idea is to use the neutron capture reaction (n,y) to determine the matrix composition to adjust the ANI calibration coefficient value. This study, dealing with 118 litres, homogeneous drums of density less than 0,4 and composed of chlorinated and/or hydrogenated materials, leads to build abacus linking the y-ray peak areas to the ANI calibration coefficient. Validation assays ofthese abacus show a very good agreement between the corrected and true fissile masses for hydrogenated matrices (max. Relative standard deviation: 23 %) and quite good for chlorinated and hydrogenated matrices (58 %). The developed correction method improves the measured values. It may be extended to 0,45 density, heterogeneous drums
Simonetti, Claude-Alexandre. "Développement d'un spectromètre/débitmètre neutrons transportable." Electronic Thesis or Diss., Normandie, 2023. http://www.theses.fr/2023NORMC262.
The DONEUT (DOsimètre NEUtrons) project in which this thesis is included, has to answer to the following issue for the civilian an military nuclear industries : a more precise determination of the neutron impact on the human body, fundamental in radiation protection.To fulfill theses requirements, which consist of measuring an ambient or personal dose equivalent rateS (H*(10) or Hp(10)) from 1 µSv/h to ~10 mSv/h in less than 10 minutes, a transportable (mass ≤ 15 kg) multi detectors cylindric prototype has been developed, with 32 thermal neutron detectors placed at different depths.This device is able to rebuild a full neutron spectrum from 0 to 20 MeV through unfolding computer codes like MAXED and GRAVEL, and the results are in good agreement with those obtained with the NNS spectrometer (Nested Neutron Spectrometer), which was our reference, with a good gamma/neutron discrimination
Ansari, Saba. "Shape evolution in neutron-rich Zr, Mo and Ru isotopes around mass A=100." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS384/document.
The shape of an atomic nucleus, ie. the deviation of its mass distribution from sphericity, is a fundamental property and governed by a delicate interplay of macroscopic and microscopic effects, such as the liquid-drop like binding energy and the nuclear shell structure, respectively. Studying nuclear shape properties using gamma ray spectroscopic methods allows detailed tests of different nuclear models, which were originally developed for stable nuclei. We proposed a project to study the evolution of nuclear shapes in exotic nuclei, far from the valley of stability, specifically in neutron-rich nuclei in the isotopic chains from Zr (Z=40) to Pd (Z=46). Usually, nuclear shapes are slowly evolving from spherical shapes around closed-shell or (doubly-) magic nuclei to elongated (prolate) shapes in nuclei with many valence nucleons. The nuclei of interest, however, show rapidly evolving patterns of excited states, which can be interpreted as rapid variations of the nuclear shape, including the rare observation of oblate (disk-like) and triaxial shapes. So far the known properties for these nuclei are (mainly) limited to excitation energies. Information on the nuclear collectivity, which can be deduced from the lifetime of the excited states, are sparse, while direct information of the shape is practically non existing. The simplest estimate of nuclear deformation in even-even nuclei can be obtained from the energy of the first 2⁺ state. For Sr (Z = 38) and Zr (Z = 40) isotopes this energy is observed to decrease dramatically at N = 60, while its evolution is much more gradual in Mo nuclei (Z = 42). Precise lifetime measurements provide a key ingredient in the systematic study of the evolution of nuclear deformation and the degree of collectivity in this region. Neutron-rich nuclei in the mass region of A = 100-120 were populated through the fusion-fission reaction of a ²³⁸U beam at 6.2 MeV/u on a ⁹Be target. The compound nucleus ²⁴⁷Cm was produced at an excitation energy of around 45 MeV before undergoing fission. The setup used for this study comprised the high-resolution mass spectrometer VAMOS in order to identify the nuclei in Z and A, the Advanced gamma ray Tracking Array AGATA of 35 germanium detectors to perform gamma ray spectroscopy, as well as a plunger mechanism to measure lifetimes down to a few ps using the Recoil Distance Doppler Shift method (RDDS). In addition, the target was surrounded by 24 Lanthanum Bromide (LaBr₃) detectors for a fast-timing measurement of lifetimes longer than 100 ps. The sophisticated set of spectrometers used in this experiment allowed measurement of nuclear lifetimes in a range from 100’s of picoseconds down to a few picoseconds. In this thesis, we will report on new lifetime results for short-lived states in neutron-rich (A ~ 100) nuclei, with an emphasis on the Zr, Mo and Ru chains. We will discuss the experimental techniques used to evaluate the lifetimes as well as their interpretation in terms of state-of-the-art nuclear structure models
Faul, Tatjana. "Etude de la Structure des Noyaux Riches en Neutrons autour du Noyau Doublement Magique 78Ni." Phd thesis, Université Louis Pasteur - Strasbourg I, 2007. http://tel.archives-ouvertes.fr/tel-00610309.
Salamon, Lino. "Transmission and capture cross section measurements by the time-of-flight technique for validation of pile-oscillation experiments in the Minerve reactor." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0312/document.
This work presents the feasibility study of transmission measurements with the MINERVE samples at time-of-flight facility GELINA. The main idea was to define procedures to analyse results of transmission measurements using cylindrical samples which do not fulfil the ideal transmission geometry. Capability of extracting reliable results was demonstrated on the example of MINERVE samples enriched in silver. In addition, transmission and capture measurements with standard discs of natural silver were performed to improve the resonance parameters for 107Ag and 109Ag. The main steps in this work are the data reduction of measured count rate spectra to produce final transmission and capture yield spectra and the spectra analysis with the resonance shape analysis code REFIT
Bastin, Beyhan. "Étude de la structure des noyaux riches en neutrons autour de la fermeture de couches N=28 par spectroscopie gamma en ligne." Caen, 2007. http://www.theses.fr/2007CAEN2072.
For a few years now, a loss of magicity in neutron-rich nuclei near the neutron drip-line at N=28 has been suggested and observed. Deformation in these nuclei has been observed. The deformation was explained in S isotopes as being due to a moderate reduction of the N=28 shell closure together with a proton induced collectivity originating from the near degeneracy of the proton d3/2 and s1/2 orbitals. As a consequence, the observed deformation seems to result from a subtle interplay between neutron and proton excitations. Since the proton configuration in the Si isotopes is expected to be more stable due to the Z=14 sub-shell gap, 42Si was considered as a key nucleus in order to distinguish the different effects responsible for the structural changes observed at N=28. Even if it is at the limits of our technical possibilities, an in-beam gamma-spectroscopy experiment using two-step fragmentation and one or several nucleons knockout reaction mechanisms was performed at GANIL. The measurement of the energy of the first excited state in 42Si, combined with the observation of 40,42Si and the spectroscopy of 41,43P, has given evidence for the loss of magicity at N=28 far from stability. Modifications of the effective interaction used in modern shell model calculations have been completed following this investigation, increasing its predictive character. This study confirms the role of the tensor force and the density dependence of the spin-orbit interaction in the collapse of the N=28 shell closure
Ma, Yue. "A study of point defects in UO₂₊ₓ and their impact upon fuel properties." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0310.
Uranium self-diffusion properties are essential for the understanding of in-reactor pellet-cladding interaction. The aim of this thesis is to determined uranium self-diffusion coefficients in hyper-stoichiometric uranium dioxide under certain thermodynamic conditions, which indeed are governed by the induced point defects. For that purpose, three separate studies were carried out on virgin material. Firstly, to improve the knowledge of oxygen defects and the rearrangements occurring in the oxygen sub-lattice after oxidation, UO₂ and UO₂₊ₓ samples were characterized by neutron diffraction in ILL Grenoble. The results obtained by a Pair Distribution Function analysis show that interstitial ions tend to be isolated at lower x but cluster at higher x. Secondly, to study the predominant uranium vacancy defects in high-temperature annealed UO₂₊ₓ, which directly influence the uranium self-diffusivity, a non-destructive method – Positron Annihilation Spectroscopy, available in CEMHTI, Orleans has been carried out. The results of Doppler broadening spectroscopy of annihilation of electron-positron pairs has proved the existence of uranium vacancies in the materials, and their concentration can be estimated based on the positron lifetime measurements using a trapping model. The knowledge of the nature relating to both cation and anion defects and defect equilibria are used to understand the correlation between important fuel properties (e.g. diffusion, creep) and thermodynamic conditions (i.e. temperature and oxygen partial pressure)
Bastin, B. "Étude de la structure des noyaux riches en neutrons autour de la fermeture de couches N=28 par spectroscopie gamma en ligne." Phd thesis, Université de Caen, 2007. http://tel.archives-ouvertes.fr/tel-00269886.
Delafosse, Clément. "Etude des dérives monopolaires neutron au-delà du 78Ni par spectroscopie gamma avec BEDO à ALTO et AGATA au GANIL." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS199/document.
Nuclear spherical shell structure evolves towards more and more exotic regions of the nuclear chart. Therefore, conventional magic numbers (2, 8, 20, 28, 50, 82, 126) can disappear while new ones appear. The evolution of gaps between single-particle states far from stability has essentially two origins : monopole drift and the collectivity enhancement. The monopole drifts are mostly coming from neutron-proton interaction (spin-isospin term of the nuclear interaction). In this thesis, we focused on the study of N=51 isotones and in particular 83Ge, the closest to 79Ni that can be studied nowadays by detailled γ-spectroscopy. For this purpose, two complementary experiments were performed. A first experiment, at GANIL with AGATA, VAMOS and the OUPS plunger device allowed us to measure lifetime of Yrast excited states in the 238U(9Be,f) reaction products. A second experiment for the study of β-delayed γ-spectroscopy of 83Ge was performed in order to populate non-Yrast states so that has an overview of the spectroscopy of 83Ge.The complementarity of these two experiments allowed highlighting for the first time an intruder state above the N=50 gap in 83Ge and thus, it adds information about the evolution of the νg9/2νd5/2 gap corresponding to the N=50 shell closure.A detailed analysis of both experiments is presented in this manuscript. In addition, a comparison to a semi-microscopic core-particle model is performed
Benmosbah, Mehdi. "Spectrométrie des neutrons : étude de la réponse d'un ensemble de compteurs proportionnels." Besançon, 2007. http://www.theses.fr/2007BESA2026.
The Rotating Spectrometer ROSPEC is made of six gaseous spherical proportionnal counters and was designed to measure the neutron fluence spectrum and provide related dosimetric data. A comparative survey with this spectrometer was carried out in 2003 on ISO neutron sources. It put forward the need for studying the effects of device rotation and for determining possible influences between the counters. By means of Monte Carlo calculations, we have shown that the rotation did not affect the measured neutron spectra but that the counter sensitive to the thermal neutrons was strongly disturbed in its immediate vicinity. .
Begin, François. "Optimisation de la mesure de spectres par scintillation liquide." Besançon, 2006. http://www.theses.fr/2006BESA2074.
Trinh, Ngoc Duy. "Emission de neutrons par les réactions d'ions lourds (4,6-95 MeV/nucléon)." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC234/document.
Heavy-ion accelerators are an essential tool for nuclear physics research. They are also adopted in several applications. It is necessary to characterize the secondary neutrons production in order to guarantee a safe operation in every circumstance in accelerators. However, experimental data are very rare or even non-existent. For some data, we notice disagreements between different publications. Disagreements are also observed between measurements data and simulations. For all these reasons, we established the program Thick Target Neutron Yields (TTNY). This program aims to measure the double differential neutron spectra (energy, angle) generated by the interactions of heavy-ions (12≤Abeam≤208 and 4.6 MeV/nucleon≤Ebeam≤95 MeV/nucleon) on thick targets (natC, natCu and natNb). Two measurements methods were adopted: Activation and Time of Flight. This choice allows having a better confidence on the measurements, studying experimental limits and consolidating the conclusions that could be drawn from the experimental results. The measurements are compared to the simulations performed with some Monte-Carlo widely used in nuclear simulation: PHITS (Japanese), FLUKA (European (CERN/INFN)) and MCNP (American). These comparisons allowed evaluating the modeling quality of heavy-ion reactions for the energies and masses explored in this work. We also conclude on the systematic uncertainties and on the potential improvements to be introduced to physics models of these codes
Ndoye, Gueye Aminata. "Conception, réalisation et test d'un capteur électronique Si-LiF-Si destiné à la spectrométrie et à la dosimétrie des neutrons." Limoges, 1998. http://www.theses.fr/1998LIMO0038.
Courrier, Benoît. "Caractérisation par spectrométrie de masse des molécules neutres induites par ablation laser." Metz, 2000. http://www.theses.fr/2000METZ057S.
Identification of neutral molecules emitted during laser materials interaction is one of the research axes developed by the Laboratoire de Spectrométrie de masse et chimie laser (LSMCL). Characterization of neutral molecules emitted during laser ablation was achived by developing a laser ablation/quadripolar mass spectrometer coupling system via gazeous chromatrography (GC/MS). The laser pyrolisis results were compared firstly those obtained by thermal pyrolisis GC/MS. They showed the strong dependance of power, the formation of aggregates and the mecanisms of decarboxylation for organic acids used as MALDI matrix. Due the introduction mode of neutral species into the chromatographic column, they was a weak sensitivity more especially for low density. The purpose of our studies was to develop and to carry out a device for identification of the neutral molecules emitted during laser ablation by increasing the detection sensitivity. Gazeous chromatography was removed and we replaced a mass spectrometer. This one is more sensitive than the GC/MS because several ionization modes can be used (electron impact EI and chemical ionization CI). When thesis is devided in two parts : the first one is confidential and will relate the presentation and the development of the device ; the second part is be devoted on the one hand, to the studied of the laser ablation of synthetic polymers and on the other hand, to the laser ablation of organic compounds used as MALDI matrix, in order to identify neutral molecules emitted
Javed, Waqas. "Etude des états conformationnels d'un transporteur ABC bactérien de drogues multiples, BmrA Functionality of membrane proteins overexpressed and purified from E. coli is highly dependent upon the strain Assemblies of lauryl maltose neopentyl glycol (LMNG) and LMNG-solubilized membrane proteins." Thesis, Université Grenoble Alpes, 2020. https://thares.univ-grenoble-alpes.fr/2020GRALV046.pdf.
Antibiotic resistance is not the story of the future but a reality today. Bacterial resistance to antibiotics can be conferred by several mechanisms, including the overexpression of dedicated efflux pumps, some of them belonging to the ABC (“ATP-binding cassette”) transporters superfamily. ABC transporters are ubiquitous proteins that use ATP hydrolysis to pump a wide range of substrates. They are also responsible for the development of MDR (“MultiDrug Resistance”) phenotypes in cancer cells and pathogenic microorganisms.The bacterial ABC exporter BmrA (“Bacillus multidrug resistance ATP”), is structurally and functionally close to ABCB1, a human transporter involved in MDR phenotypes in cancer cells. Together with extensive knowledge in its overexpression and purification, BmrA is a useful archetypical transporter to gain information on the functioning of multidrug ABC transporters. Our goal is to decipher the conformational changes associated with drug transport.We showed that BmrA exists in at least two different conformations, in detergent micelles or when reconstituted in nanodiscs. In the absence of ligand (apo form), BmrA gets quickly exchanged with deuterium as shown by Hydrogen Deuterium Exchange Coupled to Mass Spectrometry (HDX-MS). The vanadate-induced ADP trapped form shows a large overall protection against deuterium incorporation. Moreover, it was observed that BmrA in nanodiscs shows a different deuteration profile in the presence of drug, indicative of a new intermediate conformation. In addition, using two different catalytic mutants of BmrA, that are trapped in two opposite conformations of the catalytic cycle, it was shown how BmrA changes conformations during the drug export cycle. The results obtained from Small Angle Neutron Scattering (SANS), on WT BmrA and the mutants, paint a similar picture and strengthen the results obtained on the catalytic cycle of BmrA.These results could potentially lead to a better understanding of the structural basis of MDR
Nachab, Abdellatif. "Etudes expérimentales et modélisations Monte Carlo de l'auto-absorption gamma et de la dosimétrie active par capteurs CMOS." Phd thesis, Université Louis Pasteur - Strasbourg I, 2003. http://tel.archives-ouvertes.fr/in2p3-00023644.
Karam, Habib. "Mise au point de la mesure de sections efficaces de réactions (n,XN) par spectroscopie γ prompte sur des cibles très radioactives." Strasbourg, 2009. http://www.theses.fr/2009STRA6014.
The “Bataille” law obliged the CNRS to develop researches on the reprocessing of the nuclear waste. It is in this frame that our group GRACE (Groupe de Recherche sur l’Aval du Cycle Electronucléaire) of the IPHC began researches that contribute to the development of the hybrid reactors. However, the field of research widened because it now includes studies to develop the Thorium cycle. GRACE has undertaken measurements of (n,xng) reactions cross sections badly known or for which no measurement exists yet. The experiments were performed at the “white” neutron beam generated by GELINA facility in Geel, Belgium. The time of flight technique was applied. The g spectroscopy used for these measurements requires the detection of g rays with a good energy resolution. Because of the existence of a g flash created at the same time as the neutron beam, a short dead time is also required, to be able to detect the high energy neutrons. GRACE managed to conciliate these two imperatives by finalizing a new method based on the digital treatment of the signal. Using large HPGe coaxial detectors, (n,xng) cross sections measurements on the 206,207,208Pb nuclei were successfully realized at a 200 m flight path. The work presented in this thesis consists in adapting the method to highly radioactive targets. For that reason, the new measurement took place on a 30 m flight path and planar germanium detectors were used. In order to check the correct functioning of the new experimental method, (n,n’g) cross section measurements on a natural lead target were done and the results found were compared with the experiments at 200 m and with the theoretical calculations of the TALYS code. After that, the partial inelastic scattering cross sections on the 182,186W were performed from the threshold up to 8 Mev. Finally, a 93,2% enriched 235U target was bombarded and three transitions due to the 235U(n,2ng)234U reaction were successfully analysed including the one from the 8+ to the 6+ state, never measured before. This work is an essential step for using this new method in order to measure the (n,2ng) reaction cross sections on the highly radioactive 233U isotope
Hervé, Marie-Laure. "Dosimétrie d'accident en champ mixte (neutrons, photons) utilisant la spectrométrie par résonance paramagnétique électronique (RPE)." Paris 11, 2006. http://www.theses.fr/2006PA11T019.
Dubarry-Chabanais, Béatrice. "Contribution à l'étude d'un capteur électronique pour la dosimétrie personnelle des neutrons." Toulouse 3, 1992. http://www.theses.fr/1992TOU30118.
Sergeyeva, Viktoriya. "Développement d'une technique innovante de dosimétrie en réacteur pour la caractérisation du spectre neutronique dans le domaine d'énergie 1 keV - 1 MeV." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4069/document.
Reactor dosimetry goal is to reconstruct neutron spectrum in a particular reactor location. Today we can reconstruct with precision thermal (MeV) parts of neutron spectrum by using dosimeters with an adequate sensitivity. Nowadays there is no dosimeter for the intermediate energy region 1 keV - 1 MeV. Thus, the PhD goal is to select the 1 keV - 1 MeV sensible target-isotope and nuclear reaction and verify our solution by experimental irradiation. PhD final choice is for neutron capture reaction (n, γ) on 92Zr and 94Zr. Neutron irradiation produces 2 isotopes: 93Zr and 95Zr, stable and radioactive. Irradiation experiment was performed in OSIRIS reactor. Post-irradiation analyses of irradiated Zr samples are γ spectrometry and Accelerator Mass Spectrometry. In order to simulate irradiation experiment we performed calculation with neutron transport code TRIPOLI-4, based on Monte Carlo method. The goal of ZIMA (Zirconium Irradiation for Mass and Activity analysis) experiment was to prove the feasibility of 1 keV - 1 MeV neutron detection by (n,γ) capture on 92Zr and 94Zr under boron nitride filter. C/E ratios presented in this PhD allow us to conclude that activation of 94Zr and 92Zr gives us acceptable results
Mancuso, Clément. "Recherche de déformation dans des noyaux riches en neutrons." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1095/document.
Nowadays, the atomic nucleus is used in a variety of common way. Nevertheless, this object is not fully understood yet. This is why nuclear physics research is still needed. Among the large number of nuclear physics topics, this work is interested in the study of shape changes in neutron rich Ru and Sr isotopes. The subject is figured out in the first chapter, dealing with theoretical concepts about nuclear physics. A second chapter describes the experiment permitting to produce the isotopes of interest. This gamma-ray spectroscopy experiment has been realized with a HPGe multidetector made from EXOGAM and completed by GASP and LOHENGRIN detectors. This experiment consists of the cold neutron, supplied by the reactor of the Institute Laue Langevin, induced fission of 241Pu. This experiment is a part of the EXILL measurement campaign. The second chapter also deals with the data pre-analysis of this experiment. After showing the effects of a multiplicity cut on event preselection, the obtained results concerning 108Ru to 115Ru and 92Sr to 96Sr isotopes are presented on the third chapter. Finally, the fourth chapter puts these results in a wider part of the neutron rich side of both series. These last ones are also placed in their mass region context.The region of interest is rich in shape change, whether with neutronic enrichment or with excitation energy. These changes are rather well described by certain models, but the latter still have difficulty to describe the limits. Their precise determinations by experiment is essential to constrain models
Wilmsen, Dennis. "Nuclear structure studies with neutron-induced reactions : fission fragments in the N=50-60 region, a fission tagger for FIPPS, and production of the isomer Pt-195m." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC269/document.
Within the scope of atomic nuclear structure studies with neutron-induced reactions, this work presents the results of a fission fragment study in the N=50-60 region, the development of a fission event tagger, and the production of the isomer Pt-195m. Each of the different sub-topics has its origin in the 2012/13 EXILL campaign, where nuclear structure studies were carried out with neutron-induced reactions, and explored with a γ-efficient detector array. In the first part of this thesis, the neutron-rich region around neutron number N=50-60 was investigated with neutron-induced fission reactions on the fissile targets U-235 and Pu-241. Gamma spectroscopy methods were applied for the identification of the respective fission fragments, the assignment of γ transitions, and the analysis of lifetimes of excited states. The slope fit method as well as the recently developed generalized centroid difference method were used for the analysis of lifetimes in the low picoseconds to sub-nanoseconds range. Lifetimes for the nuclei Kr-92, Kr-93 and Zr-101 are presented. In the second part, first results of the development of a new detector for the discrimination of fission fragments are presented. This fission event tagger is intended to be used at the FIssion Product Prompt γ-ray Spectrometer (FIPPS) at the Institut Laue-Langevin. Within the scope of this study, two different detector designs, based on a solid plastic scintillator and an organic liquid scintillator, respectively, were tested. In the third part the possibility of the specific population of the spin-isomer in Pt-195 is discussed with special regard to its use as radioisotope in nuclear medicine. Such a specific activation could be realized via certain “doorway states” in photo-excitation reactions. The search for these doorway states was initiated within a neutron capture experiment at EXILL where potential states were found. The activation of the isomer via these states was tested afterwards with photonuclear reactions using the high intense γ-beam HIGS of the TUNL facility
Gelin, Marie. "Spectroscopie $\gamma$ des noyaux riches en neutrons autour de N=20." Phd thesis, Université de Caen, 2007. http://tel.archives-ouvertes.fr/tel-00193046.
Les noyaux suivants ont été étudiés: $^{28}$Ne, $^{30-32}$Mg, $^{31-34}$Al, $^{33-35}$Si, $^{35}$P. De nouvelles transitions ont été observées. Les distributions angulaires de rayonnements $\gamma$ ainsi que les les corrélations angulaires $\gamma$-$\gamma$ ont pu être mesurées pour certaines transitions. Une attribution des spins et parités de certains états a ainsi été proposée. En particulier, l'assignation de l'état $3^-$ dans le $^{34}$Si est confirmée et un candidat est proposé pour le second état $0^+$, correspondant à la configuration déformée. Dans le $^{32}$Mg, l'état à 2.321 MeV, pour lequel des attributions contradictioires existent, est vraisemblablement un $4^+$, et nous proposons un candidat pour un état $6^+$.
Papoular, Robert. "La spectrométrie par échos de spins de neutrons. Application à l'étude de la dynamique des polymères en solution." Paris 11, 1992. http://www.theses.fr/1992PA112092.
This work focuses on Neutron Spin Echo (NSE) spectroscopy and, particularly, on the NSE spectrometer MESS, which we have built at the L. L. B. (CEN-Saclay). After analyzing in detail the classical and quantum principles of this type of instrument, and illustrated them with optical analogies, we expound a simple formalism for the interpretation of polarized neutron experiments of the most general type. In a second part, we describe the MESS spectrometer extensively: its characteristics and performances as well as the first physics results obtained with this instrument. In particular, we include two papers showing how the neutron depolarization, spin rotation and echoes can be used to investigate high-Tc superconductors. The last part deals with the dynamics of Polymer-Polymer-Solvent ternary solutions and demonstrates how the Neutron Spin Echo technique becomes a privileged tool for such physico-chemical studies thanks to the joint use of NSE and contrast variation methods, coupled with the adequate ranges of time and scattering vectors accessible. Finally, we describe the specific case of partially deuterated polydimethylsiloxane (PDMS) in semi-dilute solution in Toluene. We have experimentally and separately evidenced the cooperative and interdiffusive diffusion modes predicted by the theory of Akcasu, Benoit, Benmouna et al. These results, obtained at the L. L. B. (CEN-Saclay) are the subjectmatter of the last paper included in this work
Belleguic-Pigeard, de Gurbert Marjorie. "Spectroscopie γ en ligne au moyen de la fragmentation du projectile au G. A. N. I. L. : structure des noyaux riches en neutrons autour de N = 20." Lyon 1, 2000. http://www.theses.fr/2000LYO10077.
Martins, Da Silva Fernando Henrique. "Etude structurale, distribution cationique et état d'oxydation dans des nanoparticules magnétiques de ferrite du type coeur-coquille." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066102/document.
Structural properties of core-shell ferrite nanoparticles MFe2O4 (M = Mn and Co) and Mn-Zn ferrite nanoparticles are here investigated. The nanoparticles are synthesized by hydrothermal co-precipitation and are dispersed in acid medium thanks to an empirical surface treatment by ferric nitrate, which prevents the chemical dissociation by a thin maghemite layer incorporated at the surface of the nano-grains. Chemical titrations allow us to calculate volume fractions of core and shell, as well as the surface-layer thickness. Structural changes induced by the surface treatment are followed as a function of treatment duration in MnFe2O4 and CoFe2O4 nanocrystals. Whereas structural changes in Mn-Zn ferrite nanoparticles are investigated as a function of zinc content. X-ray and Neutron diffractions are used to determine the structural parameters, in particular cationic distribution in the spinel ferrite sites. Precise structural information with high degree of reliability is obtained by Rietveld refinements. To investigate the local structure of these materials, X-ray Absorption Spectroscopy measurements are performed, allowing determining interatomic distances, mean oxidation state and inversion degree. Morphology, crystallinity and size of mixed-ferrite nanoparticles are investigated by TEM/HRTEM and electron diffraction. In Mn-Zn ferrite nanoparticles, the presence of Mn3+ in octahedral environment is responsible for anisotropic distortions, known as Jahn-Teller effect. The inversion degree obtained in this work diverges from the bulk values due to the reduction to nanoscale and to the increase of the surface/volume ratio, associated to the synthesis process
Cheminet, Adrien. "Développement d'un système opérationnel de spectrométrie des neutrons dédié à la caractérisation dynamique de l'environnement radiatif naturel atmosphérique à l'Observatoire du Pic du Midi de Bigorre." Thesis, Toulouse, ISAE, 2013. http://www.theses.fr/2013ESAE0028.
This PhD Thesis has been achieved thanks to the joint effort between two French organizations, the French Institute for Radiological Protection and Nuclear Safety (IRSN/LMDN, Cadarache) and the French Aerospace Lab (ONERA/ DESP, Toulouse). The aim was to develop an operational neutron spectrometer extended to high energies in order to measure the dynamics of the spectral variations of the natural radiative environment at the summit of the Pic du Midi Observatory in the French Pyrenees. Thereby, the fluence responses of each detector were calculated thanks to Monte Carlo simulations. Afterwards, they were validated by means of experimental campaigns up to high energies (>20 MeV) nearby reference neutron fields. The systematic uncertainties were deduced after detailed studies of the mathematic reconstruction of the spectra (i.e. unfolding procedure). Then, the system was tested under rocks at the LSBB of Rustrel before being installed at respectively+500 m and +1000 m above sea level for the first environmental campaigns. Finally, the spectrometer has been operating for two years after its deployment at the summit of the Pic du Midi (+2885 m). The continuous data were analysed thanks to an innovative method. Some seasonal and spectral variations were observed. Some Forbush decreases were also recorded after strong solar flares. These data were further analysed thanks to Monte Carlo simulations. The data were made more attractive thanks toseveral practical applications with personal dosimetry or reliability of submicron electronics components
Gironnet, Johann. "Spectrométrie de neutrons rapides par bolomètres à cible lithium pour la réduction du fond des expériences de détection directe de matière noire." Phd thesis, Paris 11, 2010. http://tel.archives-ouvertes.fr/tel-00633437.
Teyssier, Cécile. "Spectrométrie de masse COINTOF : Conception et d'un analyseur à temps de vol et développement de la méthode d'analyse." Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00744850.
Thiry, Jean-Claude. "Measurement of (n,xng) reaction cross sections of interest for the Generation IV reactors." Strasbourg, 2010. http://www.theses.fr/2010STRA6144.
The presented work consists of studying 232Th(n,xnγ) and 235U(n,xnγ) reactions in the fast neutron energy domain (up to 20 MeV) with the best precision possible. The experiments are performed at GELINA which delivers a pulsed, white neutron beam at IRMM, Belgium. The time characteristics of the beam enable us to measure neutron energies with the time-of-flight (TOF) technique. The neutron induced reactions (in this case inelastic scattering, (n,2n) and (n,3n) reactions) are identified by online prompt γ spectroscopy with an experimental setup including four HPGe detectors. A double layered fission chamber is used to monitor the incident neutron flux. The obtained results are presented and a comparison between the measured cross sections and the TALYS code predictions will be discussed. In order to achieve a very high precision on the reaction cross sections, an extensive work has been realised on the detection efficiencies of the counters used in the experiment. These quantities were in fact the largest sources of uncertainty in foregoing campaigns. After important efforts including high precision measurements together with Geant4 simulations, the efficiency of the fission chambers as well as of the HPGe detectors could be determined with accuracies below 3 %, accomplishing the final goal of a cross section determination with a precision of 5 %. This work is a further step in the preparation of the measurement of 233U(n,xnγ) reactions, which are completely unknown at this stage although of very high importance in the 232Th regeneration process. For this reason, a new, segmented HPGe detector was conceived, which will complete the current experimental setup
Carrel, Frédérick. "Etude et développement d’une technique de dosage des actinides dans les colis de déchets radioactifs par interrogation photonique ou neutronique active et spectrométrie des gamma retardés." Caen, 2007. http://www.theses.fr/2007CAEN2022.
An accurate estimation of the alpha-activity of a nuclear waste package is necessary to select the best mode of storage. The main purpose of this work is to develop a non-destructive active method, based on the fission process and allowing the identification of actinides (235U, 238U, 239Pu). These three elements are the main alpha emitters contained inside a package. Our technique is based on the detection of delayed gammas emitted by fission products. These latter are created by irradiation with the help of a neutron or photon beam. Performances of this method have been investigated after an Active Photon or Neutron Interrogation (INA or IPA). Three main objectives were fixed in the framework of this thesis. First, we measured many yields of photofission products to compensate the lack of data in the literature. Then, we studied experimental performances of this method to identify a given actinide (239Pu in fission, 235U in photofission) present in an irradiated mixture. Finally, we assessed the application of this technique on different mock-up packages for both types of interrogation (118 l mock-up package containing EVA in fission, 220 l mock-up package with a wall of concrete in photofission)
Lucas, Bruno. "Spectroscopie infrarouge couplée à la spectrométrie de masse pour la caractérisation en phase gazeuse de petits systèmes moléculaires neutres ou protonés." Paris 13, 2004. http://www.theses.fr/2004PA132014.
Rąpała, Michał. "Etude de la fission nucléaire par spectrométrie des rayons gamma prompts." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS390/document.
The desire to improve the fuel efficiency of nuclear reactors has motivated new solutions in their design. One of them is the heavy reflector used in the generation III+ and in the future generation IV reactors. γ-rays passing through matter cause its excitation and temperature rise. It is a process called γ-heating, and it is responsible for more than 90% of the heat production in the non-fuel region of the nuclear reactor. This is also the case of the heavy reflector. To simulate the γ-heating effect in every state of the nuclear reactor it is necessary to have precise data on the prompt γ-rays emitted by different fission fragments produced in the course of the nuclear chain reaction. In 2012, at the research reactor of the ILL, an innovative experiment, called EXILL, was conducted. It produced a large amount of useful data on the de-excitation of the fission fragments. A large number of HPGe detectors were used to study the neutron induced fission process by measuring the emitted γ-rays. Fissile targets were irradiated by an intense cold neutron beam. In this work we analyzed the ²³⁵U targets. We studied several fission fragments and more generally the fission process by using high-resolution γ-ray spectroscopy. At the beginning, we used the standard γ-γ-γ coincidence analysis method. We were able to filter experimental data, identify the well produced γ-rays, and calculate their relative intensities. The problems we have encountered are related to the background. The results obtained with this method were background dependent and thus presented some problems with reproducibility. We therefore developed and tested a new analysis methodology. Its crucial feature is a coincidence gates scanning in three directions which helps to find the most suitable background. The idea was to move from a “spectroscopic” method, which main purpose is finding new transitions and excited states in a nucleus, to a “spectrometric” method, which allows us to obtain more precise γ-ray intensities. We developed a semi-automatic analysis software which facilitates fitting of the chosen γ-ray peak, the contamination and the background. Various γ-ray intensity calculation schemes were derived to take into account different contamination strengths and placements. The results of the analysis with the new technique are reproducible and more reliable. The standard and the new analysis method were compared in the ¹⁴²Ba analysis. In this work, we also compared our experimental results on some nuclei, such as ¹⁰⁰Zr, with the simulation results performed with the FIFRELIN code. It is a Monte-Carlo code which simulates the fission process and the de-excitation of the fission fragments. It uses various models to describe these processes. We were able to test the behavior of different models implemented in FIFRELIN to find the optimal simulation parameter values and to test how well these setups reproduce the experimental results. FIFRELIN was unable to simultaneously reproduce the γ-ray intensities of ¹⁰⁰Zr and the prompt-neutron multiplicity averaged over all fission fragments. However, with modified simulation parameters, FIFRELIN locally provided correct prompt-neutron multiplicity for the fission fragment with the atomic mass A=100 and well reproduced γ-ray intensities of ¹⁰⁰Zr. We also compared our experimental results on ¹⁰⁰Zr coming from the ²³⁵U(n,f) process with the other available experimental data coming from the experiments on ²⁴⁸Cm(sf) and ²⁵²Cf(sf), and another experiment on ²³⁵U(n,f)
Roy, Sandrine. "Analyse des bio-marqueurs de la maladie de Fabry par techniques séparatives couplées et spectrométrie de masse." Paris 11, 2005. http://www.theses.fr/2005PA114841.
Fabry disease in an X-linked inborn error of neutral glycosphingolipids (GSLs) metabolism, caused by a deficiency of the lysomal α-galactosidase A, wich results in high levels of globotriaosylceramide (Gb3) and galabiosylceramide (Ga2). Different techniques are developed to analyse lipid classes and molecular species in each lipid class. First, we optimised the separation of four major neutral GSLs. An HPLC separation combined with evaporative light-scattering detection allowed the detection of urinary globotriaosylceramide in urinary sediments of patients. Second, we analysed the different molecular species of Gb3 and Ga2 in urinary sediments with tandem mass spectrometry (MALDI Q-TOF and HPLC APPI MS-MS). About twenty molecular species are identified for Gaé and Gb3. Third, these lipids were analysed directly on the surface of tissue sections. MALDI-TOF ond cluster-TOF-SIMS imaging approaches were used to obtain the localization of GSLs on skin and kidney sections of patients affected by the Fabry disease
Steichen, Valentin. "Développement d’un analyseur en énergie pour la caractérisation des hautes atmosphères neutres et ionisées terrestre et planétaires." Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS635.
Studying the dynamic of particles in the thermosphere – ionosphere and in the exosphere of bodies in the Solar System allows to deepen our understanding of these critical regions that are the bridge between a planet and space. The aim of my thesis was to develop, build and test a neutral particles energy analyser for studying the upper planetary atmospheres: INEA (Ion and Neutral Energy Analyser). The instrument aims to measure the energy structure of the neutral and ion constituents present in the upper atmosphere. To achieve this challenging task, INEA relies on two concepts: an innovative ion source that is based on a carbon nanotube array as an electron emitter and an electrostatic energy analyser which is able to image directly the energy distribution of the particles. During these three years of thesis, a numerical model of INEA was developed in order to meet the instrumental objectives imposed by the measurements needed to characterize the upper atmospheres. At the same time, I have been working on the development of an ion source, also necessary for the optimal operation of INEA, based on the use of carbon nanotubes as electron emitters. The development of the detector, another important part of the instrument has also been conducted. Following the numerical modelling and the work achieved on the different parts of the instrument, a first prototype of INEA has been designed and assembled. This prototype being currently tested. With the work achieved during this thesis, we have been able to propose two instruments for future space missions: M-INEA on the M-MATISSE mission proposed for the ESA M7 call for project, recently selected for a phase A study up to mid-2026, and PSEE, an electron emitter dedicated to the control of PRELUDE SAT, a 6U CubeSat developed by two Japanese universities scheduled to be launched mid-2025
Gey, Guillaume. "Etude de noyaux riches en neutrons dans la région du coeur doublement magique de ¹³²Sn." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENY033/document.
Evolution of nuclear structure in the vicinity of the doubly magic nuclei 132Sn will be discussed in this work, through the spectroscopy of 136Sb, 136Sn and 138Sn isotopes. Several Sb and Sn known isotopes beyond the Z=50 and N=82 shell closures will be briefly presented in the first chapter, aswell as some of the problems arising from the current shell model descritpion of nuclei in this region. Reader will also find in the same chapter a brief description of the most important tools needed to understand such calculations. Excited state of 136Sb have been populated at the Institut Laue-Langevin (Grenoble) through thermal neutron-induced fission on a 241Pu target. Fission fragments produced were separated with the Lohengrin mass spectrometer. Conversion electrons and gammas from 136Sb were measured and confirmed the previously proposed schemed. A new 31(7) ns isomer has been measured and assigned to the 4- state. Details of the experiment and analysis are presented in the first part. The second part is devoted to the 136,138Sn isotopes, produced via in-flight fission of 238U on a 9Be target at the RIBF of the RIKEN (Tokyo). Mass separators BigRIPS and ZDS allowed separation and identification of produced fragments, before implantation in the higly segmented silicon detector WAS3ABi surrounded by the germanium array EURICA. The first energy measurement of the 6+ -> 4+, 4+ -> 2+ and 2+ -> 0+ transitions has been performed for each of the 136,138Sn isotopes, aswell as an 46(7) and 219(58) ns half-life for the 6+ state of the 136Sn and 138Sn respectively
Stanoiu, Mihai Alexandru. "Spectroscopie gamma en ligne de noyaux légers riches en neutrons produits par fragmentation de faisceau radioactif et mesures de temps de vie des niveaux excités dans les noyaux proches du 68Ni." Caen, 2003. http://www.theses.fr/2003CAEN2010.
Moussaoui, Roba. "Study of negative ions surface production in cesium-free H2 and D2 plasmas." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0328/document.
This thesis deals with negative ions (NI) surface production for applications in thermonuclear fusion. This work was conducted using a plasma source PHISIS. NI formed on a negatively biased sample surfaceare collected and analyzed with energy mass spectrometer (MS). Negative ion distribution function NIEDF is measured. A SIMION calculation was done to have a complete idea about MS transmission effect on the NIEDF. In the course of this thesis, a DC pulsed bias technique is introduced to enable the study of negative ion surface production on insulating samples as non-doped diamond layers. A model that calculate the rate of change of bias on insulator surface biased in pulsed mode is developed. Surprisingly, negative-ion surface production on boron-doped or non-doped diamond is much higher in pulsed mode than in continuous mode. This thesis deals also with negative ion surface production in low bias condition. The best NI yield measured at low bias is obtained with Boron doped diamond (BDD) ant it is 2 times higher than the one measured on HOPG (highly oriented pyrolytic graphite) surface. Analysis of NI surface production at different surface bias for different material were performed in order to correlate the NI yield evolution to the surface state changes.An extensive study of NI surface production was performed on Nanoporous 12CaO.7Al2O3 electride surface. The influence of surface temperature, bias and plasma exposure time on negative-ion yield was investigated. In this contribution, we show that the electride material has potentials to be used as a production surface in negative ion sources devoted to nuclear fusion application
Bréard, Yohann. "Synthèse, structure et propriétés d'oxydes et d'oxycarbonates en couches dans les systèmes Sr-Fe-Co-O et Sr-Fe-M-C-O (M = SC, Cr, Mn, Co et Ni)." Caen, 2002. http://www.theses.fr/2002CAEN2037.
Roussiere, Brigitte. "Contribution à l'étude de noyaux impairs, déficients en neutrons, de platine (A = 187,185,183) et d'osmium (A = 183) : déformations nucléaires et anomalies de conversion interne." Paris 11, 1986. http://www.theses.fr/1986PA112340.
The ¹ ⁸⁷, ¹ ⁸⁵, ¹ ⁸³Pt and ¹ ⁸³Os nuclei, located in a region of shape instability , have been studied from the β+/CE decay of gold nuclei produced by the Pt(p(200 MeV),xn) Au reaction then mass-separated using the ISOCELE II Isotope separator. For these four nuclei, levels schemes have been built from γ-γ-t and γ-e--t coincidence relationships and conversion electron measurements. Two very converted transitions have been observed in ¹ ⁸⁵Pt, but none in ¹ ⁸³Pt and ¹ ⁸³Os. The ¹ ⁸⁷Pt nucleus has been also studied from the 176Yb(16O(93 MeV), 5nγ) reaction to connect the low spin states to the high spin states. Experimental results have been interpreted in the frame of the "rotor axial + quasi-particle HF" modal. Ali the states located below 600 keV in ¹ ⁸⁵Pt, ¹ ⁸³Pt and ¹ ⁸³Os correspond to a "prolate" shape of the nucleus. But, to interpret le lowest states of negative parity in ¹ ⁸⁷Pt, it is necessary either to consider an oblate-prolate shape coexistence or to take into account the γ-asymmetry parameter (as in the interpretation of the high spin levels of these nuclei). The anomalous M1 multipolarity has been attributed firmly to one of the very converted transitions of ¹ ⁸⁵Pt since the spin values of the states connected by this transition are different. The second very converted transition of ¹ ⁸⁵Pt is located between two states that we have interpreted as prolate-shaped states. Thus it seems that very converted transitions are not due to shape coexistence phenomenon. Complementary experiments are proposed in order to improve our knowledge of these conversion anomalies
Coulon, Romain. "Spectrométrie gamma haute résolution et hauts taux de comptage sur primaire de réacteur de type génération 4 au sodium liquide." Phd thesis, Caen, 2010. http://www.theses.fr/2010CAEN2040.
Sodium-cooled Fast Reactors are under development for the fourth generation of nuclear reactor. Breeders reactors could gives solutions for the need of energy and the preservation of uranium resources. An other purpose is the radioactive wastes production reduction by transmutation and the control of non-proliferation using a closed-cycle. These thesis shows safety and profit advantages that could be obtained by a new generation of gamma spectrometry system for SFR. Now, the high count rate abilities, allow us to study new methods of accurate power measurement and fast clad failure detection. Simulations have been done and an experimental test has been performed at the French Phénix SFR of the CEA Marcoule showing promising results for these new measurements
Coulon, Romain. "Spectrométrie gamma haute résolution et hauts taux de comptage sur primaire de réacteur de type génération 4 au sodium liquide." Phd thesis, Université de Caen, 2010. http://tel.archives-ouvertes.fr/tel-00564868.