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1. In situ Phenotyping of Grapevine Root System Architecture by 2D or 3D Imaging: Advantages and Limits of Three Cultivation Methods

Author

Yuko Krzyzaniak, Frédéric Cointault, Camille Loupiac, Eric Bernaud, Frédéric Ott, Christophe Salon, Anthony Laybros, Simeng Han, Marie-Claire Héloir, Marielle Adrian, and Sophie Trouvelot

Subjects
root system architecture, root traits, grapevine, phenotyping, rhizotron, neutron tomography, Plant culture, SB1-1110
Abstract

The root system plays an essential role in the development and physiology of the plant, as well as in its response to various stresses. However, it is often insufficiently studied, mainly because it is difficult to visualize. For grapevine, a plant of major economic interest, there is a growing need to study the root system, in particular to assess its resistance to biotic and abiotic stresses, understand the decline that may affect it, and identify new ecofriendly production systems. In this context, we have evaluated and compared three distinct growing methods (hydroponics, plane, and cylindric rhizotrons) in order to describe relevant architectural root traits of grapevine cuttings (mode of grapevine propagation), and also two 2D- (hydroponics and rhizotron) and one 3D- (neutron tomography) imaging techniques for visualization and quantification of roots. We observed that hydroponics tubes are a system easy to implement but do not allow the direct quantification of root traits over time, conversely to 2D imaging in rhizotron. We demonstrated that neutron tomography is relevant to quantify the root volume. We have also produced a new automated analysis method of digital photographs, adapted for identifying adventitious roots as a feature of root architecture in rhizotrons. This method integrates image segmentation, skeletonization, detection of adventitious root skeleton, and adventitious root reconstruction. Although this study was targeted to grapevine, most of the results obtained could be extended to other plants propagated by cuttings. Image analysis methods could also be adapted to characterization of the root system from seedlings.

Published
2021
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2. Pore Structure and Water Transfer in Pietra d’Aspra Limestone: A Neutronographic Study

Author

Luciana Randazzo, Giuseppe Paladini, Valentina Venuti, Vincenza Crupi, Frédéric Ott, Giuseppe Montana, Michela Ricca, Natalia Rovella, Mauro Francesco La Russa, and Domenico Majolino

Subjects
neutron radiography, porous limestones, consolidants, water kinetics, artificial weathering, capillarity, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999
Abstract

Neutron radiography (NR) was here applied to study the effects of two different commercially available consolidants on the water absorption properties in a particular type of limestone (biocalcarenite), known as Pietra d’Aspra stone, which is one of the most extensively used lithotypes in Sicilian Baroque buildings. Our attention was mainly focused on the evaluation, using a fast and nondestructive visualization of water motion through capillarity, of the effectiveness of such layers as consolidating agents in view of preserving and maintaining both old and modern structures. The biocalcarenite was treated with nanosilica (Nano Estel®) and nanolime (CaLoSil®) by brushing it until full saturation, and then artificially weathered by salt crystallization and temperature/relative humidity jumps. Liquid distribution and height of the water front were monitored as a function of time. Significant differences in the water suction behavior among all the investigated samples were highlighted, which allowed us to gain insight into the coating/substrate interaction mechanisms which regulate the fluid mobility inside the porous network of the limestone.

Published
2020
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3. Neutron Radiography Study of Laboratory Ageing and Treatment Applications with Stone Consolidants

Author

Matea Ban, Tim De Kock, Frédéric Ott, Germana Barone, Andreas Rohatsch, and Simona Raneri

Subjects
neutron radiography, stone consolidation, treatment application, artificial ageing, water absorption, brushing, poultice, capillary absorption, Chemistry, QD1-999
Abstract

A nano-silica consolidant and nano-titania modified tetraethyl-orthosilicate were applied on two building stones, a carbonate and a silicate, by brush, poultice or capillary absorption. Neutron radiography was used to monitor capillary water absorption, and to analyse changes in physical properties caused by heat treatment of specimens for the purposes of artificially ageing and different treatment applications with stone consolidants. Moreover, ultrasonic pulse velocity and gravimetrically determined water absorption were analysed to cross-validate neutron radiography. The results reveal that reactive systems like tetraethyl-orthosilicates need an unknown period for polymerisation, which makes nano-silica consolidants more favourable for construction follow-up work. While polymerisation is incomplete, hydrophobic behaviour, water trapping and pore clogging are evident. Within the tetraethyl-orthosilicate treatment, poultice and brushing are strongly influenced by the applicant, which results in wide ranging amounts of water absorbed and anomalous water distributions and kinetics. The carbonate lithotype displays polymerisation initiated in the core of the specimen, while the lateral surfaces are still mostly hydrophobic. Reaction time differences can be attributed to the different amounts of consolidants applied, which is a result of the chosen application settings. Artificial ageing of stone specimens is a prerequisite when mechanical strength gain is studied, as demonstrated by sound speed propagation.

Published
2019
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4. Pseudo-random time modulation technique for neutron diffraction instruments on compact accelerator-driven neutron sources

Author

Frédéric Ott

Subjects
Nuclear and High Energy Physics, Nuclear Energy and Engineering
Abstract

Time modulation methods are routinely used on neutron scattering time-of-flight instruments, which exploit the time structure of neutron pulses for energy determination. In the past, complex time modulation methods were proposed, either to maximize the neutron flux which can be used, or to increase the energy resolution of the measurements. In this article, we explore the possibilities offered by such methods and in particular random modulation using statistical choppers to improve the performances of the DIoGENE scattering instrument installed around the IPHI-neutron CANS source at Saclay. We conclude that when the source is operated in continuous mode, the implementation of a statistical chopper is very efficient to perform either metallurgical studies such as strain scanning or phase transition studies. Random modulation techniques may be easily and efficiently implemented because the high capacity of modern computers enables high-speed data processing from large surface pixelated detectors.

Published
2023
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5. Neutron scattering on DIoGENE at IPHI–neutrons

Author

Jacques Darpentigny and Frédéric Ott

Subjects
Nuclear and High Energy Physics, Nuclear Energy and Engineering
Abstract

The IPHI–Neutrons facility is a low energy neutron CANS ( E p = 3 MeV) used to test various technologies for the construction of high current CANS (HiCANS). Part of the research program includes the investigation of the possibility to perform neutron scattering and radiography experiments around CANS. For this purpose, the DIoGENE instrument has recently been installed around the IPHI source. The instrument is aimed as a general-purpose neutron scattering instrument featuring 256 high-pressure 3 He tubes covering a solid angle of 0.74 sr. The instrument is especially suited for diffraction experiments but may be upgraded as a SANS or reflectometry instrument. We are using the DIoGENE instrument to investigate the performances of the neutron TMR, the issues related to background noise due to fast neutrons and gamma rays productions and more generally the ToF data acquisition protocols and processing in event mode. We present in this communication the recent diffraction results obtained on DIoGENE during the tests of the new high power Be target on IPHI–Neutrons.

Published
2023
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6. Long term operation of a 30 kW Beryllium target at IPHI

Author

Jérôme Schwindling, Burkhard Annighöfer, Nicolas Chauvin, Jean-Louis Meuriot, Borana Mom, Frédéric Ott, Nadia Sellami, and Loïc Thulliez

Subjects
Nuclear and High Energy Physics, Nuclear Energy and Engineering
Abstract

Following tests of low power bulk Beryllium targets in 2016–2020, a high power target was designed, built and tested at the High Intensity Proton Injector (IPHI) at CEA Paris–Saclay. The design of the target and the results of the tests will be described.

Published
2023
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7. Opportunities in the use of Very Cold Neutrons in reflectometry techniques

Author

Frédéric Ott

Subjects
Nuclear and High Energy Physics, Nuclear Energy and Engineering
Abstract

Reflectometry techniques are especially suited for time-of-flight measurements. The use of longer wavelengths does not modify the physics probed during a reflectivity measurement. Besides, reflectometry measurements are not affected by effects such as multiple scattering or absorption. The use of longer wavelengths would permit to achieve instrumental gains. Indeed, in the scattering plane, the phase space can be used more efficiently by a geometrical factor proportional to λ 2 provided by a simple increase of the incidence angles on the sample (for a given Q range). Perpendicular to the scattering plane, the neutron flux can be increased by a factor proportional to λ due to the increased critical angle of optics used for focusing in this direction. However, to comply with a given pulse structure of the neutron source would either require to proportionally decrease the instrument length or to drop neutron frames. Both options are viable depending on the scientific goals and we show that the flux penalties are actually minimal. However, owing to the fact that the performances of reflectometry instrumentation at ESS are expected to be extremely high, it is questionable if it is worth investing in Very Cold Neutrons (VCN) production for this specific technique the more so as the implementation will not be optimal for extrinsic reasons. On the other hand, implementing VCN on sources such as CANS where the flux is intrinsically limited may be worth the investment since (i) such sources could probably be designed to use VCN in an optimal way, (ii) the construction and handling of VCN sources would be much easier as radiative heating would be reduced by several orders of magnitude, in the range of hundreds of watts.

Published
2023
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8. SONATE, a French CANS for materials science research

Author

Frédéric Ott, Christiane Alba-Simionesco, Alain Menelle, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear engineering, 0103 physical sciences, Project plan, 010306 general physics, 01 natural sciences, ComputingMilieux_MISCELLANEOUS, Atomic and Molecular Physics, and Optics
Abstract

Since 2015, the Laboratoire Leon Brillouin (LLB), operated by the CEA and the CNRS in France, has been developing a project plan to build a facility using a compact accelerator driven neutron sourc...

Published
2020
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9. Exact resolution function for double-disk chopper neutron time-of-flight spectrometers: application to reflectivity

Author

Didier Lairez, Frédéric Ott, Alexis Chennevière, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Physics - Instrumentation and Detectors, Spectrometer, Physics::Instrumentation and Detectors, Gaussian, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), 02 engineering and technology, 021001 nanoscience & nanotechnology, 010403 inorganic & nuclear chemistry, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, 0104 chemical sciences, Computational physics, Chopper, Time of flight, Wavelength, symbols.namesake, Tilt (optics), symbols, Curve fitting, Physics::Accelerator Physics, Neutron, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 0210 nano-technology
Abstract

International audience; The exact resolution function in transfer vector for the reflectometer HERM\`ES at Laboratoire L\'eon Brillouin is calculated as an example of neutron time-of-fligh spectrometer with double-disk chopper. Calculation accounts for wavelength distribution of the incident beam, tilt of the chopper axis, collimation and gravity, without approximation of gaussian distributions or independence of these different contributions. Numerical implementation is provided that matches the sections of the paper. We show that data fitting using this exact resolution function allows us to reach much better results than its usual approximation by a gaussian profile.

Published
2020
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11. Coupling dependent reversal in Co/Pt based mixed anisotropy multilayer stacks

Author

Frédéric Ott, Anastasios Markou, Laurentiu Stoleriu, A. Stancu, and Ioannis Panagiotopoulos

Subjects
010302 applied physics, Coupling, Materials science, Condensed matter physics, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Magnetization, Magnetic anisotropy, Domain wall (magnetism), Stack (abstract data type), Remanence, 0103 physical sciences, Neutron reflectometry, 0210 nano-technology, Anisotropy
Abstract

A series of multilayers [Co(6)/Pt(15)]4/(Pt(s))/[Co(10)/Pt(15)]4 (thicknesses in A) consisting from a perpendicular magnetic anisotropy [Cο(6)/Pt(15)]4-stack (PA) coupled to an in-plane anisotropy [Cο(10)/Pt(15)]4-stack (IPA) through the variable Pt interlayer (with s = 0–45 A), is studied as a model mixed-anisotropy system. Vector vibrating sample magnetometry and polarized neutron reflectometry show that, at remanence, the magnetization of each stack relaxes to its own easy axis, with the exception of the s = 0. For the s = 0 sample, the strong coupling between the two different anisotropy stacks results in a collective reversal of both stacks. This process corresponds to an averaged effective uniaxial anisotropy, which suppresses the PA characteristics. For the rest of the samples the stacks are weakly coupled and separate reversal of the two stacks occurs. The PA stack reverses by rapid domain wall motion under the influence of the IPA which has relaxed to its own easy plane. The remaining coupling, despite being weak, influences the values and angular dependence of the reversal fields as well as the positions of positive/negative and doublets on the First Order Reversal Curve (FORC) distributions.

Published
2019
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12. Polarized neutron channeling in weakly magnetic films

Author

Thomas Keller, Frédéric Ott, V. D. Zhaketov, Kai Chen, S. V. Kozhevnikov, Chen Luo, Florin Radu, and Yu. N. Khaydukov

Subjects
010302 applied physics, Physics, Condensed Matter - Materials Science, Nuclear and High Energy Physics, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Microbeam, Impulse (physics), Polarization (waves), 01 natural sciences, Wavelength, Magnetization, Planar, 0103 physical sciences, Neutron, Magnetic films, Atomic physics, 010306 general physics, Instrumentation
Abstract

We describe a new sensitive method for the investigation of weakly magnetic films placed inside a tri-layer planar waveguide. Polarized neutrons tunnel into the waveguide through the surface, channel along the layers and are emitted from the end face as a narrow and slightly divergent microbeam. Polarization analysis permits to detect very small magnetization in the order of a few 10 Gauss. The magnetic film containing the rare-earth element Tb was investigated using both fixed wavelength and time-of-flight polarized neutron reflectometers. The experimental results are presented and discussed., Submitted to NIM A

Published
2019
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13. Channeling of Neutrons in a Nonmagnetic Planar Waveguide

Author

S. V. Kozhevnikov, Florin Radu, Yu. N. Khaydukov, Thomas Keller, and Frédéric Ott

Subjects
Materials science, Solid-state physics, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Middle layer, Nuclear Theory, General Physics and Astronomy, Microbeam, 01 natural sciences, law.invention, Optics, Planar, law, 0103 physical sciences, Neutron, Thin film, Nuclear Experiment, 010306 general physics, business, Layer (electronics), Waveguide
Abstract

The propagation of neutrons in the middle layer of a planar waveguide, which is a three-layer thin film, has been studied. Neutrons emitted from the end of the film in the form of a narrow divergent microbeam have been detected. The neutron channeling length has been measured experimentally as a function of the width of the waveguiding layer. The experimental results are compared with calculations.

Published
2019
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14. In situ Phenotyping of Grapevine Root System Architecture by 2D or 3D Imaging: Advantages and Limits of Three Cultivation Methods

Author

Anthony Laybros, Christophe Salon, Marielle Adrian, Sophie Trouvelot, Camille Loupiac, Yuko Krzyzaniak, Marie-Claire Héloir, Frédéric Cointault, Eric Bernaud, Frédéric Ott, Simeng Han, Agroécologie [Dijon], Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Procédés Alimentaires et Microbiologiques [Dijon] (PAM), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), LLB - Nouvelles frontières dans les matériaux quantiques (NFMQ), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, 0301 basic medicine, Root (linguistics), phenotyping, Context (language use), Root system, Plant Science, Biology, rhizotron, 01 natural sciences, Skeletonization, SB1-1110, 03 medical and health sciences, Cutting, [SDV.SA.STA]Life Sciences [q-bio]/Agricultural sciences/Sciences and technics of agriculture, Methods, 2. Zero hunger, root system architecture, Neutron tomography, Rhizotron, Plant culture, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], 15. Life on land, Hydroponics, grapevine, 2D/3D imaging, 030104 developmental biology, root traits, neutron tomography, Biological system, 010606 plant biology & botany
Abstract

International audience; The root system plays an essential role in the development and physiology of the plant, as well as in its response to various stresses. However, it is often insufficiently studied, mainly because it is difficult to visualize. For grapevine, a plant of major economic interest, there is a growing need to study the root system, in particular to assess its resistance to biotic and abiotic stresses, understand the decline that may affect it, and identify new ecofriendly production systems. In this context, we have evaluated and compared three distinct growing methods (hydroponics, plane, and cylindric rhizotrons) in order to describe relevant architectural root traits of grapevine cuttings (mode of grapevine propagation), and also two 2D- (hydroponics and rhizotron) and one 3D- (neutron tomography) imaging techniques for visualization and quantification of roots. We observed that hydroponics tubes are a system easy to implement but do not allow the direct quantification of root traits over time, conversely to 2D imaging in rhizotron. We demonstrated that neutron tomography is relevant to quantify the root volume. We have also produced a new automated analysis method of digital photographs, adapted for identifying adventitious roots as a feature of root architecture in rhizotrons. This method integrates image segmentation, skeletonization, detection of adventitious root skeleton, and adventitious root reconstruction. Although this study was targeted to grapevine, most of the results obtained could be extended to other plants propagated by cuttings. Image analysis methods could also be adapted to characterization of the root system from seedlings.

Published
2021
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15. DLI-MOCVD Crx Cy coating to prevent Zr-based cladding from inner oxidation and secondary hydriding upon LOCA conditions

Author

Jean-Christophe Brachet, Francis Maury, Stéphane Urvoy, Frédéric Ott, Elodie Rouesne, M. Dumerval, G. Nony, Frédéric Schuster, Alexandre Michau, M. Le Saux, Service des Recherches Métallurgiques Appliquées (SRMA), Département des Matériaux pour le Nucléaire (DMN), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Recherche Dupuy de Lôme (IRDL), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Service d'études analytiques et de réactivité des surfaces (SEARS), Département de Physico-Chimie (DPC), Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Department of Environment and Conservation, Government of Western Australia - DECCommissariat à l'Énergie Atomique et aux Énergies Alternatives - CEA, École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Toulouse (UT)

Subjects
Cladding (metalworking), Nuclear and High Energy Physics, Materials science, Hydrogen, chemistry.chemical_element, 02 engineering and technology, Chemical vapor deposition, post-quenching strength and ductility, Enhanced Accident Tolerant Fuel, engineering.material, 7. Clean energy, 01 natural sciences, high temperature steam oxidation, 010305 fluids & plasmas, Corrosion, secondary hydriding, Coating, 0103 physical sciences, General Materials Science, Composite material, LOCA, Zircaloy-4, Quenching, Zirconium, Nuclear fuel, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Nuclear Energy and Engineering, chemistry, engineering, CrxCy DLI-MOCVD inner coating, 0210 nano-technology
Abstract

International audience; Zirconium-based claddings with an outer chromium coating resistant to corrosion are studied and devel- oped as an evolutionary Enhanced Accident Tolerant Fuel (E-ATF) concept for light water reactors. How- ever, in hypothetical LOss-of-Coolant-Accident (LOCA) conditions, following clad ballooning and burst, the outer coating does not allow to protect the inner surface of the cladding from High Temperature (HT) steam oxidation and associated secondary hydriding due to steam starvation occurring within the gap between the clad inner surface and the nuclear fuel pellets. To address this issue, DLI-MOCVD (Direct Liquid Injection of Metal-Organic precursors - Chemical Vapor Deposition) Cr x C y coatings have been developed and successfully deposited onto the inner surface of Zr- based cladding tube prototypes. Then, preliminary two-sided oxidation tests have shown that such inner coating is able to increase the resistance to oxidation at HT of the inner clad surface. The present study aimed at performing new steam oxidation tests at 1200 °C on Zircaloy-4 clad proto- types with a 5–20μm-thick Cr x C y inner coating, in conditions more representative of LOCA, after a first internal pressure-induced burst step. Additionally, complementary two-sided steam oxidation tests have been carried out up to 1 h at 1200 °C, on short inner and/or outer-coated clad segments. Finally, Post- Quench (PQ) Ring Compression Tests (RCTs), fractographic analysis and deep metallurgical investigations including neutron-tomography have been performed to get more insights into the PQ behavior of the inner-coated clad. Among other results, it is shown that the inner Cr x C y coating makes it possible to reduce significantly the oxidation and the associated secondary hydriding of the clad inner surface, after ballooning and burst. After at least 600 s under steam at 1200 °C, the reference uncoated clad fails upon final water quenching while the inner-coated prototype keeps its integrity. PQ RCTs showed a higher strength of the inner- coated material, related to lower oxygen and hydrogen uptakes of the substrate.

Published
2021
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16. Multi-scale characterization by neutronography and electron diffraction of Ni coating on Cu-Ni-Al or cast-iron glass molds after laser cladding

Author

Arnaud Courteaux, Frédéric Ott, Fazati Bourahima, Michel Rege, Thierry Baudin, François Brisset, Anne-Laure Helbert, Vincent Ji, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Baudin, Thierry

Subjects
MEB/EDS/EBSD, Materials science, Scale (ratio), [SPI] Engineering Sciences [physics], 02 engineering and technology, engineering.material, 01 natural sciences, Multi-scale analysis, 010309 optics, [SPI]Engineering Sciences [physics], Coating, [CHIM] Chemical Sciences, 0103 physical sciences, [CHIM]Chemical Sciences, General Materials Science, Mechanical Engineering, Metallurgy, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Laser cladding, Characterization (materials science), Electron diffraction, Mechanics of Materials, engineering, Cast iron, 0210 nano-technology, Neutronography
Abstract

International audience; Laser cladding of a Ni based powder on Cu-Ni-Al or cast iron was performed with a 4kW continuous Nd: YAG laser. The Cu-Ni-Al and cast-iron substrates are used for their thermal properties in glass mold industry. But the issue of these materials is their lack of resistance on corrosion and abrasion. The role of the Ni based alloy is to protect the mold without affecting its thermal properties (Heat Affected Zone (HAZ)). The purpose of this research is to produce a well bonded Ni based melted powder without pores or cracks on a non-planar surface (curvilinear section). An investigation of the impact of the processing parameters, power (1500-3200 W), scanning speed (2.5-10 mm/s) and powder feeding rate (24.5-32.5 g/min) on the bonding quality, the porosity propagation and HAZ appearance is performed. The used methods are neutronography, Scanning Electron Microscopy, Energy Dispersive Spectroscopy and Electron BackScatter Diffraction (EBSD). These multi-scale techniques are obviously complementary. Neutronography is a well-adapted non-destructive method to observe the porosity in the volume thanks to the contrast between materials. EBSD analysis allows us to analyze the microstructural evolution of the coating notably by observing the dendrites growth. This same method also permits to observe the HAZ nature according to the laser cladding parameters. Those methods allowed to optimize the processing parameters in a way to obtain perfect bonding, to avoid porosity propagation and to limit the HAZ emergence.

Published
2020

17. Divergence of neutron microbeams from planar waveguides

Author

V. D. Zhaketov, Florin Radu, Thomas Keller, Yu. N. Khaydukov, S. V. Kozhevnikov, and Frédéric Ott

Subjects
Nuclear and High Energy Physics, FOS: Physical sciences, Physics::Optics, 01 natural sciences, symbols.namesake, Optics, Planar, 0103 physical sciences, High spatial resolution, Neutron, 010306 general physics, Divergence (statistics), Instrumentation, 010302 applied physics, Physics, Condensed Matter - Materials Science, business.industry, Materials Science (cond-mat.mtrl-sci), Microbeam, Fraunhofer diffraction, Neutron radiation, Computer Science::Other, Wavelength, symbols, Physics::Accelerator Physics, business
Abstract

Neutron planar waveguides are focusing devices generating a narrow neutron beam of submicron width. Such a neutron microbeam can be used for the investigation of local microstructures with high spatial resolution. The essential parameter of the microbeam is its angular width. The main contribution to the microbeam angular divergence is Fraunhofer diffraction on a narrow slit. We review and discuss various ways to characterize the angular divergence of the neutron microbeam using time-of-flight and fixed wavelength reflectometers., 17 pages, 16 figures. Submitted to NIM A

Published
2019
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18. Comparison of the thermal neutron scattering treatment in MCNP6 and GEANT4 codes

Author

Anthony Marchix, Alain Menelle, Nicolas Chauvin, H.N. Tran, J. Schwindling, Jacques Darpentigny, Frédéric Ott, and A. Letourneau

Subjects
Physics, Nuclear and High Energy Physics, Neutron transport, 010308 nuclear & particles physics, Beryllium oxide, Scattering, Nuclear engineering, chemistry.chemical_element, 01 natural sciences, Neutron temperature, chemistry.chemical_compound, Cross section (physics), chemistry, Aluminium, 0103 physical sciences, Neutron source, Neutron, 010306 general physics, Instrumentation
Abstract

To ensure the reliability of simulation tools, verification and comparison should be made regularly. This paper describes the work performed in order to compare the neutron transport treatment in MCNP6.1 and GEANT4-10.3 in the thermal energy range. This work focuses on the thermal neutron scattering processes for several potential materials which would be involved in the neutron source designs of Compact Accelerator-based Neutrons Sources (CANS), such as beryllium metal, beryllium oxide, polyethylene, graphite, para-hydrogen, light water, heavy water, aluminium and iron. Both thermal scattering law and free gas model, coming from the evaluated data library ENDF/B-VII, were considered. It was observed that the GEANT4.10.03-patch2 version was not able to account properly the coherent elastic process occurring in crystal lattice. This bug is treated in this work and it should be included in the next release of the code. Cross section sampling and integral tests have been performed for both simulation codes showing a fair agreement between the two codes for most of the materials except for iron and aluminium.

Published
2018
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19. Channeling of Neutrons in the Potential Well of a Planar Waveguide

Author

Frédéric Ott, Yu. N. Khaidukov, S. V. Kozhevnikov, and Florin Radu

Subjects
010302 applied physics, Physics, Solid-state physics, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Hadron, Physics::Optics, General Physics and Astronomy, Fermion, Impulse (physics), 01 natural sciences, law.invention, Optics, Planar, law, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, business, Nucleon, Waveguide
Abstract

The channeling of neutrons in a three-layer planar waveguide with a neutron-optical potential well is studied. Neutrons incident on a sample surface, which propagate in a middle layer and escape from the waveguide end in the form of a narrow divergent beam, are detected. The decay parameter of a neutron wave inside the waveguide is measured as a function of the potential well depth. Experimental results are compared with a theory.

Published
2018
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20. Consolidation of cobalt nanorods: A new route for rare-earth free nanostructured permanent magnets

Author

Lise-Marie Lacroix, Konstantin P. Skokov, Jean-Yves Piquemal, Oliver Gutfleisch, Evangelia Anagnostopoulou, Semih Ener, Thomas Blon, Frédéric Ott, Guillaume Viau, I. Dirba, Technische Universität Darmstadt (TU Darmstadt), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LLB - Nouvelles frontières dans les matériaux quantiques (NFMQ), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Darmstadt - Technical University of Darmstadt (TU Darmstadt), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris Diderot - Paris 7 (UPD7)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Institut für Materialwissenschaft, Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UPS), and Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS UMR7086)

Subjects
Diffraction, Materials science, Polymers and Plastics, energy product, chemistry.chemical_element, Alnico, 02 engineering and technology, Neutron scattering, engineering.material, 7. Clean energy, 01 natural sciences, Rod, bottom-up, Cobalt nanorods, 0103 physical sciences, [CHIM]Chemical Sciences, Composite material, [PHYS]Physics [physics], 010302 applied physics, permanent magnets, Metals and Alloys, [CHIM.MATE]Chemical Sciences/Material chemistry, Coercivity, 021001 nanoscience & nanotechnology, Electronic, Optical and Magnetic Materials, chemistry, Magnet, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Ceramics and Composites, engineering, Nanorod, 0210 nano-technology, Cobalt, consolidation process
Abstract

International audience; Rare-earth free permanent magnets were produced by consolidation of cobalt nanorods synthesized by the polyol process exhibiting a mean diameter in the range 10e30 nm. Compactions of magnetically prealigned rod assemblies at various pressures and temperatures were carried out to make dense materials. Bulk magnets exhibiting a very good mechanical strength and an energy product as high as 65 kJ m À3 were obtained. The best results were obtained when the compaction conditions were soft enough to preserve the morphology and alignment of the rods in the final material, as revealed by X-ray diffraction and neutron scattering. For the first time the bottom-up approach is convincingly reported to produce bulk magnets without the addition of any matrix, the obtained nanostructured materials exhibit coercivity much higher than the AlNiCo magnets and can fill the performance " gap " between hexaferrites and rare-earth based magnets.

Published
2018
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22. Channeling of Neutrons in a Planar Waveguide

Author

Frédéric Ott, V. D. Zhaketov, Florin Radu, S. V. Kozhevnikov, and Yu. N. Khaydukov

Subjects
010302 applied physics, Materials science, Solid-state physics, business.industry, General Physics and Astronomy, Resonance, Microbeam, 01 natural sciences, Optics, Planar, 0103 physical sciences, Waveguide (acoustics), Neutron, Thin film, 010306 general physics, business, Layer (electronics)
Abstract

The propagation of neutrons in the middle layer of a planar waveguide in the form of a three-layer thin film has been investigated. The microbeam from the end face of the film has been registered. The neutron channeling length has been measured as a function of the thickness of the upper waveguide layer and the resonance order. The experimental data have been compared with theoretical results.

Published
2017
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23. Characterization methods for neutron channeling in planar waveguides

Author

Yu. N. Khaydukov, Thomas Keller, Florin Radu, S. V. Kozhevnikov, and Frédéric Ott

Subjects
010302 applied physics, Physics, Nuclear and High Energy Physics, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Neutron scattering, Neutron radiation, 01 natural sciences, law.invention, Planar, Optics, Characterization methods, law, 0103 physical sciences, High spatial resolution, Neutron, Neutron reflectometry, Nuclear Experiment, 010306 general physics, business, Instrumentation, Waveguide
Abstract

Neutron planar waveguides produce a narrow neutron beam of submicron width which can be used to scan local microstructures with high spatial resolution. The important parameter of a planar waveguide is the distance over which the neutron wave density decays exponentially during the neutron channeling inside a guiding layer. We review various ways to experimentally characterize neutron channeling lengths. Experimental results are presented and advantages and drawbacks of the different methods are discussed.

Published
2017
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24. Neutron Zeeman beam-splitting for the investigation of magnetic nanostructures

Author

E. Semenova, Frédéric Ott, and S.V. Kozhevnikov

Subjects
Physics, Condensed Matter - Materials Science, Nanostructure, Zeeman effect, Condensed matter physics, Magnetism, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, 02 engineering and technology, Neutron scattering, Neutron radiation, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, symbols.namesake, 0103 physical sciences, symbols, Neutron, Neutron reflectometry, Electrical and Electronic Engineering, Thin film, 010306 general physics, 0210 nano-technology
Abstract

The Zeeman spatial splitting of a neutron beam takes place during a neutron spin-flip in magnetically non-collinear systems at grazing incidence geometry. We apply the neutron beam-splitting method for the investigation of magnetically non-collinear clusters of submicron size in a thin film. The experimental results are compared with ones obtained by other methods., 11 pages, 9 figures

Published
2017
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25. Evaluating the protecting effects of two consolidants applied on Pietra di Lecce limestone: A neutronographic study

Author

Domenico Majolino, Michela Ricca, Mauro Francesco La Russa, Frédéric Ott, Giuseppe Paladini, Vincenza Crupi, Valentina Venuti, Luciana Randazzo, Natalia Rovella, Randazzo L., Venuti V., Paladini G., Crupi V., Majolino D., Ott F., Ricca M., Rovella N., and La Russa M. F.

Subjects
Consolidants, Limestone, Neutronography, Sorptivity, Water kinetics, Archeology, Absorption of water, Materials science, Materials Science (miscellaneous), Mineralogy, 02 engineering and technology, Conservation, 01 natural sciences, Water kinetics, Consolidants, Consolidant, Sorptivity, Relative humidity, Limestone, Neutronography, Spectroscopy, Salt crystallization, Settore GEO/09 -Georis. Miner.e Appl.Mineral.-Petrogr. per l'Ambi.ed i B.Cult, 010401 analytical chemistry, Wetting front, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Chemistry (miscellaneous), 0210 nano-technology, General Economics, Econometrics and Finance
Abstract

In this work a combined laboratory-based and neutronographic investigation was carried out on a type of limestone, known as Pietra di Lecce stone, widely used in Italian Baroque as construction material. The limestone was treated with two different commercially-available coatings, namely nanosilica and nanolime, and artificially weathered by salt crystallization and temperature/relative humidity jumps. The aim was to provide an experimental evidence of the protective and consolidating effectiveness of the two treatments by looking at the water absorption process occurring inside the pore network of the analyzed stones. The analysis of the wetting front position revealed significant variations in the water absorption kinetics among the investigated samples, suggesting different mechanisms of interaction between the inorganic consolidants and the underlying bulk stone. Finally, a quantitative evaluation of the best effectiveness of the two products was addressed, particularly useful in view of an appropriate choice of restoration procedures to be applied to building materials.

Published
2020

26. From soft chemistry to 2D and 3D nanowire arrays with hard magnetic properties and permanent magnet applications

Author

Frédéric Ott, Guillaume Viau, Lise-Marie Lacroix, Bruno Chaudret, Katerina Soulantica, Thomas Blon, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay

Subjects
010302 applied physics, Materials science, Magnetism, Nanowire, Nanotechnology, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Coercivity, 021001 nanoscience & nanotechnology, 7. Clean energy, 01 natural sciences, Magnetization, Magnetic anisotropy, Magnet, 0103 physical sciences, Magnetic nanoparticles, Nanorod, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

The polyol method and the organometallic chemistry route are two liquid-phase processes which have proven to be well suited for the synthesis of high aspect ratio ferromagnetic nanoparticles with an excellent crystallinity. Cobalt nanowires and nanorods with a mean diameter in the range 5–40 nm and exhibiting very high magnetic anisotropy and more complex anisotropic particles such capped nanowires or core-shell nanowires and nanorods can be prepared by these methods. The organometallic route was also extended to the growth of 2D hexagonal arrays of cobalt nanowires of diameter in the range 5–10 nm, combining chemical reduction and epitaxy. The particles prepared by the liquid-phase process are model systems for studying the magnetism of anisotropic objects as well as the interactions between magnetic nanoparticles. Several micromagnetic studies were carried out to describe the effect of the particle shape and crystallinity on the coercivity of elongated cobalt nanoparticles. These studies provided useful guidelines for particle optimization to reach the best possible properties for permanent magnet applications. The excellent properties in terms of magnetization (Ms = 1.7 T) and coercivity (μ0HC = 0.3–1 T) of cobalt nanorods make them candidates for the fabrication of permanent magnets and for applications in the field of magnetic recording. 3D permanent magnets with an energy product, (BH)max, of 65 and 165 kJ m− 3 were prepared by alignment and consolidation of cobalt nanorods. The bottom-up approach appears very promising to prepare new hard magnetic materials with BHmax that can fill the gap between ferrites and rare-earth-based magnets.

Published
2020
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27. Contributors

Author

Flavio Abreu Araujo, João P. Araújo, A. Asenjo, E. Berganza, F. Béron, Juan Maria Blanco, Thomas Blon, Tim Böhnert, C. Bran, Hans-Benjamin Braun, Sergey Bunyaev, Mattia Butta, Rafael Caballero, Olga Caballero-Calero, E. Calle, Tristan da Câmara Santa Clara Gomes, R.B. Campanelli, Michalis Charilaou, George Chatzipirpiridis, Bruno Chaudret, Xiang-Zhong Chen, Horia Chiriac, A. Chizhik, O. Chubykalo-Fesenko, Paula Corté-Leon, A.S.E. da Cruz, Rafael P. del Real, L. Herrera Diez, Patrick R. Downey, D. Estevez, L. Fecova, Amalio Fernández-Pacheco, J.A. Fernandez-Roldan, Alison B. Flatau, Rhonda Franklin, L. Frolova, O. Fruchart, L. Galdun, J. Galik, J. Gamcova, Javier García, P. Gawroński, J. Gonzalez, Silvia González, D. Gusakova, Masamitsu Hayashi, M. Hennel, R. Hudak, L. Hvizdos, Jerome K. Hyun, P. Ibarra, Mihail Ipatov, Yu.P. Ivanov, M. Jaafar, Bumjin Jang, R. Jurc, Gleb Kakazei, P. Klein, Jürgen Kosel, D. Kozejova, Joaquín de la Torre Medina, Lise-Marie Lacroix, Jörg F. Löffler, Nicoleta Lupu, Eduardo Martínez, Marisol Martín-González, Miguel Méndez, O. Milkovic, K.O. Moura, Chaitanya Mudivarthi, D. Mudronova, Manuel Muñoz, David Navas, Bradley J. Nelson, Michael Van Order, Frédéric Ott, Tibor-Adrian Óvári, P.J.G. Pagliuso, Salvador Pané, Larissa V. Panina, Martha Pardavi-Horvath, Jung Jin Park, Eva Pellicer, Jose E. Perez, Luc Piraux, K.R. Pirota, M. Poggio, Victor M. Prida, José L. Prieto, Mariana P. Proenca, Josep Puigmartí-Luis, F.X. Qin, Victor Raposo, D. Ravelosona, Kotha Sai Madhukar Reddy, K. Richter, A. De Riz, T. Ryba, R. Sabol, Dédalo Sanz-Hernández, Semih Sevim, Anirudh Sharma, E. Snoeck, Katerina Soulantica, Célia T. Sousa, Bethanie J.H. Stadler, A. Stupakiewicz, I. Sulla, Sang-Yeob Sung, Liwen Tan, Elena V. Tartakovskaya, Ch. Thirion, Jacob Torrejon, J.-Ch. Toussaint, B. Trapp, Joseph Um, R. Varga, Z. Vargova, M. Vázquez, Victor Vega, João Ventura, Guillaume Viau, Shixiong Zhang, Yali Zhang, Wen Zhou, Arcady Zhukov, Valentina Zhukova, and Jia Zou

Published
2020
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28. The SONATE project, a french CANS for materials sciences research

Author

Alain Menelle, Frédéric Ott, Christiane Alba-Simionesco, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Accelerator Physics (physics.acc-ph), Range (music), QC1-999, [PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph], FOS: Physical sciences, 01 natural sciences, 7. Clean energy, law.invention, Optics, law, 0103 physical sciences, 010306 general physics, Spectroscopy, Physics, Condensed Matter - Materials Science, 010308 nuclear & particles physics, business.industry, Reference design, Resolution (electron density), Peak current, Materials Science (cond-mat.mtrl-sci), Particle accelerator, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Neutron source, Physics - Accelerator Physics, business, Energy (signal processing)
Abstract

International audience; We describe the Compact Accelerator-based Neutron Source SONATE which we are aiming for to replace the close Orphée reactor at Saclay, France. The SONATE source would serve an instrumental suite of about 10 instruments. The instruments would be split into low resolution instruments and higher resolution instruments. Our reference design is based on a proton accelerator operating at an energy in the range 20-30 MeV. The accelerator would serve 2 target stations. The first one operating at 20Hz with 2ms long pulses serving low resolution instruments (SANS, reflectivity, imaging, spin-echo) and the second one operating at 100Hz, 200µs long pulses serving higher resolution instruments (powder diffraction, Direct Time-of-flight spectroscopy, Indirect geometry spectroscopy). The 2 operation modes would be interlaced. The peak current on the target is aimed at 100 mA with an average power on the target on the order of 50-80 kW. Numerical Monte-Carlo simulations show that we may expect instrument performances equivalent to the current instruments around Orphée or ISIS.

Published
2020
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29. UCANS – 8, Paris, July 8-11 th 2019 Eighth International Meeting of the Union of Compact Accelerator-based Neutron Sources

Author

Frédéric Ott, Alain Menelle, Christiane Alba-Simionesco, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay

Subjects
[PHYS]Physics [physics], Engineering, 010308 nuclear & particles physics, business.industry, Physics, QC1-999, [PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph], Astronomy, 01 natural sciences, 0103 physical sciences, Neutron source, 010306 general physics, business, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2020
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31. System of neutron microbeams from a planar waveguide

Author

S. V. Kozhevnikov, A. V. Petrenko, Yu. V. Nikitenko, Frédéric Ott, and Vladimir K. Ignatovich

Subjects
Wavelength, Planar, Optics, Materials science, Physics and Astronomy (miscellaneous), Solid-state physics, business.industry, Waveguide (acoustics), Neutron, Space (mathematics), business
Abstract

Results of experimental investigations of space, angular and wavelength distribution in neutron microbeams obtained for the first time with the help of a resonant planar neutron waveguide at the time-of-flight reflectometer of the IBR-2 pulsed reactor are reported and comparison with theoretical calculations is presented. Possible application of microbeams in physical experiments is discussed.

Published
2015
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32. Methods for Probing Magnetic Films with Neutrons

Author

Florin Radu, S. V. Kozhevnikov, Frédéric Ott, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Larmor precession, Physics, Nuclear and High Energy Physics, Zeeman effect, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Resonance, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, symbols.namesake, 0103 physical sciences, symbols, Magnetic films, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Spin (physics), Beam (structure)
Abstract

International audience; We review various methods in the investigation of magnetic films with neutrons, including those based on the effects of Larmor precession, Zeeman spatial splitting of the beam, neutron spin resonance, and polarized neutron channeling. The underlying principles, examples of the investigated systems, specific features, applications, and perspectives of these methods are discussed.

Published
2018
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33. Neutron imaging and tomography: Applications in food science

Author

Arnaud Hélary, Camille Loupiac, Sylvain Desert, Simone Scussat, Frédéric Ott, Physico-Chimie de l'Aliment et du Vin (PCAV), Procédés Alimentaires et Microbiologiques [Dijon] (PAM), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
010308 nuclear & particles physics, Neutron imaging, Physics, QC1-999, 02 engineering and technology, Neutron radiation, 021001 nanoscience & nanotechnology, Object (computer science), 01 natural sciences, Sample (graphics), 0103 physical sciences, Fuel cells, Tomography, Food science, 0210 nano-technology, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition
Abstract

International audience; Neutron imaging and tomography allow observing the structure of large objects (from few to hundred centimeters) at a resolution around 100 μm. This non-destructive method is based on the detection of the transmission of a neutron beam through an object in 2D (imaging) or 3D after rotating the sample (tomography). The components of the object attenuate the neutron beam differently, depending on their composition, and produce accurate pictures of objects which give information about their structure. Neutron imaging has been used for quality control purposes in industries (aircraft, motor engineering...), but also find application from materials sciences (fuel cells, lithium batteries) through earth science (petrology, geology) to cultural heritage. More recently studies have been performed on food science topics.

Published
2018
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34. The impact of cooking on meat microstructure studied by low field NMR and Neutron Tomography

Author

Luc Delmotte, Simone Scussat, Frédéric Ott, Philippe Cayot, Cyril Vaulot, Camille Loupiac, Procédés Alimentaires et Physico-Chimie (PAPC), Procédés Alimentaires et Microbiologiques (PAM), Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Laboratoire de Matériaux à Porosité Contrôlée (LMPC), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Ecole Nationale Supérieure de Chimie de Mulhouse-Centre National de la Recherche Scientifique (CNRS), projet Open Food System, Procédés Alimentaires et Physico-Chimie ( PAPC ), Procédés Alimentaires et Microbiologiques ( PAM ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Institut de Science des Matériaux de Mulhouse ( IS2M ), Université de Haute-Alsace (UHA) Mulhouse - Colmar ( Université de Haute-Alsace (UHA) ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Léon Brillouin ( LLB - UMR 12 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Matériaux à Porosité Contrôlée ( LMPC ), Université de Haute-Alsace (UHA) Mulhouse - Colmar ( Université de Haute-Alsace (UHA) ) -Ecole Nationale Supérieure de Chimie de Mulhouse-Centre National de la Recherche Scientifique ( CNRS ), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
0301 basic medicine, Low field NMR, Meat, Strong interaction, Analytical chemistry, Bioengineering, Calorimetry, Applied Microbiology and Biotechnology, Meat fibers, Endothermic process, Neutron tomography, 03 medical and health sciences, 0404 agricultural biotechnology, Nuclear magnetic resonance, [SDV.IDA]Life Sciences [q-bio]/Food engineering, Denaturation (biochemistry), Microstructure, Cooking temperature, 030109 nutrition & dietetics, Chemistry, Relaxation (NMR), [ SDV.IDA ] Life Sciences [q-bio]/Food engineering, food and beverages, 04 agricultural and veterinary sciences, 040401 food science, Food Science
Abstract

International audience; We studied the impact of temperature of cooking on meat microstructure. The cooking temperature was verified by calorimetry, showing the disappearance of endothermic peaks when cooking temperature was increased. These observations correspond to the denaturation of different protein fractions at specific temperatures. 1H-low field NMR and neutron tomography were used to further understand the relationship between the observed protein denaturation and changes in meat microstructure after heating. Hahn’s echo and solid echo NMR sequences were applied to observe fast relaxation time corresponding to rigid protons. These protons were found to be associated with pools of protons with a strong interaction with the meat matrix. Their relaxation times (T2) are of order of 500–900 μs (for Hahn’s echo sequence) and 10 μs (for solid echo’s sequence). These protons become more rigid upon increasing the temperature. 3D neutron tomography analysis demonstrated the defects created by the contraction of meat fibers and allowed measurement of their volume, which increase for the highest cooking degrees. This analysis allowed classification of the defects as a function of their position (surface or interior) and size (threshold 0.075 % v/v). Our results demonstrate that large defects increase increasing cooking temperature and are located at the surface of the meat slice.

Published
2017
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35. Study of secondary hydriding at high temperature in zirconium based nuclear fuel cladding tubes by coupling information from neutron radiography/tomography, electron probe micro analysis, micro elastic recoil detection analysis and laser induced breakdown spectroscopy microprobe

Author

Caroline Raepsaet, Jean-Christophe Brachet, Jean-Luc Lacour, Frédéric Ott, Elodie Rouesne, Valérie Vandenberghe, Guy Bayon, Jean-Luc Béchade, Didier Hamon, Matthieu Le Saux, Stéphane Urvoy, Caroline Toffolon-Masclet, Service des Recherches Métallurgiques Appliquées (SRMA), Département des Matériaux pour le Nucléaire (DMN), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Service de recherches de métallurgie physique (SRMP), Laboratoire d'Etudes des Eléments Légers (LEEL - UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Service d'études analytiques et de réactivité des surfaces (SEARS), Département de Physico-Chimie (DPC), SEROS (SEROS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Service des Recherches Métallurgiques Appliquées ( SRMA ), Département des Matériaux pour le Nucléaire ( DMN ), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Service de recherches de métallurgie physique ( SRMP ), Laboratoire d'Etudes des Eléments Légers ( LEEL - UMR 3685 ), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) ( NIMBE UMR 3685 ), Centre National de la Recherche Scientifique ( CNRS ) -Institut Rayonnement Matière de Saclay ( IRAMIS ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ) -Institut Rayonnement Matière de Saclay ( IRAMIS ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Service d'études analytiques et de réactivité des surfaces ( SEARS ), Département de Physico-Chimie ( DPC ), SEROS ( SEROS ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Laboratoire Léon Brillouin ( LLB - UMR 12 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), CEA-Direction de l'Energie Nucléaire (CEA-DEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay

Subjects
Nuclear and High Energy Physics, Microprobe, Materials science, Hydrogen, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Secondary hydriding, Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, Electron microprobe, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, hydrogen concentrations, 0103 physical sciences, General Materials Science, Laser-induced breakdown spectroscopy, LOCA, 010302 applied physics, Zirconium, m-ERDA, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Cladding (fiber optics), Multiscale quantification of oxygen and, Neutron radiography and tomography, Elastic recoil detection, Surface coating, Nuclear Energy and Engineering, chemistry, 13. Climate action, PWR nuclear fuel cladding, [ CHIM.MATE ] Chemical Sciences/Material chemistry, EPMA, 0210 nano-technology
Abstract

International audience; This paper gives an overview of a multi-scale experimental study of the secondary hydriding phenomena that can occur in nuclear fuel cladding materials exposed to steam at high temperature (HT) after having burst (loss-of-coolant accident conditions). By coupling information from several facilities, including neutron radiography/tomography, electron probe micro analysis, micro elastic recoil detection analysis and micro laser induced breakdown spectroscopy, it was possible to map quantitatively, at different scales, the distribution of oxygen and hydrogen within M5™1 clad segments having experienced ballooning and burst at HT followed by steam oxidation at 1100 and 1200 °C and final direct water quenching down to room temperature. The results were very reproducible and it was confirmed that internal oxidation and secondary hydriding at HT of a cladding after burst can lead to strong axial and azimuthal gradients of hydrogen and oxygen concentrations, reaching 3000–4000 wt ppm and 1.0–1.2 wt% respectively within the β phase layer for the investigated conditions. Consistent with thermodynamic and kinetics considerations, oxygen diffusion into the prior-β layer was enhanced in the regions highly enriched in hydrogen, where the α(O) phase layer is thinner and the prior-β layer thicker. Finally the induced post-quenching hardening of the prior-β layer was mainly related to the local oxygen enrichment. Hardening directly induced by hydrogen was much less significant.

Published
2017
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36. First steps toward the development of SONATE, a Compact Accelerator driven Neutron Source

Author

L. Thulliez, Jérôme Schwindling, Frédéric Ott, Alain Menelle, A. Letourneau, Nadia Sellami, Burkhard Annighöfer, and Nicolas Chauvin

Subjects
Physics, Brightness, Neutron flux, QC1-999, Nuclear engineering, Detector, Neutron source, Spallation, Context (language use), Neutron, Neutron temperature
Abstract

Facilities providing bright thermal neutron beams are of primary importance for various research topics such as condensed matter experiments, neutron-imaging or medical applications. Currently these are mainly spallation sources and nuclear reactors. However, these later facilities are ageing and the political context does not favor the building of new ones. This is the case in CEA-Saclay (France), where the Orphee reactor is planned to shutdown in 2019. Therefore, another local facility, affordable by one country, able to provide high brilliance neutron beams has to be built. At CEA-Saclay, a compact accelerator driven neutron source, SONATE, is investigated in taking advantage of the IPHI accelerator able to deliver a 3 MeV proton beam with an intensity up to 100 mA. In the future, SONATE is foreseen to operate with 20 MeV protons to increase the neutron brightness. In addition to the difficulties to operate such high intensity accelerators, the other challenges regard the target-moderator-reflector (TMR) design which is crucial to maximize the neutron flux at the detector location. At CEA-Saclay, several experiments were performed between 2016 and 2019 with the IPHI accelerator. Geant4 simulations were also developed. They demonstrate the feasibility of such concept and enable to find the best TMR configuration for the future SONATE facility. These developments are reported in this article.

Published
2020
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37. Application of a polarized neutron microbeam to the investigation of a magnetic microstructure

Author

André Thiaville, Manuel Vázquez, Jacob Torrejon, Frédéric Ott, and S. V. Kozhevnikov

Subjects
Waveguide (electromagnetism), Materials science, Solid-state physics, Magnetic domain, business.industry, Microbeam, Neutron radiation, Condensed Matter Physics, Microstructure, Electronic, Optical and Magnetic Materials, Amorphous solid, Nuclear magnetic resonance, Optics, Neutron, business
Abstract

The application of a neutron microbeam to the investigation of an internal magnetic microstructure has been demonstrated experimentally. The object of investigation is an amorphous magnetic wire 190 μm in diameter, with the axial and circular magnetic domains formed inside it. A narrow neutron microbeam with a width of 2.6 μm, which is formed by a three-layer film (a planar waveguide) serves as the probe for scanning with a high spatial resolution. The method of investigation is the neutron spin precession upon transmission through the sample. © 2014 Pleiades Publishing, Ltd., This study was supported by the IMAMINE 2010-09T project (France).

Published
2014
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38. Experimental determination of the neutron channeling length in a planar waveguide

Author

Frédéric Ott, Vladimir K. Ignatovich, S. V. Kozhevnikov, A. Rühm, and Janos Major

Subjects
Physics, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Physics::Optics, General Physics and Astronomy, Microbeam, Neutron radiation, Neutron scattering, law.invention, Optics, Planar, law, Neutron, Neutron reflectometry, Atomic physics, Exponential decay, Nuclear Experiment, business, Waveguide
Abstract

In neutron waveguides, the neutron wave is confined inside the guiding layer of the structure and can escape from the layer edge as a microbeam. The channeling within the guiding layer is accompanied by an exponential decay of the neutron wave function density inside the waveguide. Here, we report direct determination of the corresponding decay constant, termed the neutron channeling length. For this, we measured the microbeam intensity as a function of the length of a neutron absorbing layer of variable length placed onto the surface of a waveguide structure. Such planar neutron waveguides transform a conventional neutron beam into an extremely narrow but slightly divergent microbeam, which can be used for the investigation of nanostructures with submicron spatial resolution.

Published
2013
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39. Magnetic planar waveguides as combined polarizers and spin-flippers for neutron microbeams

Author

Janos Major, A. Rühm, Florin Radu, S. V. Kozhevnikov, and Frédéric Ott

Subjects
Physics, Nuclear and High Energy Physics, business.industry, Physics::Optics, Microbeam, Polarizer, law.invention, Wavelength, Optics, Planar, law, Optoelectronics, Neutron, business, Instrumentation, Waveguide, Beam (structure), Spin-½
Abstract

We propose waveguide structures which transform an incident unpolarized beam into a polarized microbeam and also can be used as spin-flippers by varying the incidence angle on the structure. We describe optimized structures combining these functions. Such waveguides could be used for the investigation of one-dimensional magnetic structures and could be implemented on any existing fixed wavelength reflectometer.

Published
2013
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40. Development of compact accelerator neutron source

Author

Frédéric Ott, Anthony Marchix, A. Letourneau, Nicolas Chauvin, Alain Menelle, Ngoc-Hoang Tran, and Jérôme Schwindling

Subjects
Physics, Brightness, Proton, 010308 nuclear & particles physics, 020502 materials, Nuclear engineering, Astrophysics::High Energy Astrophysical Phenomena, QC1-999, Nuclear Theory, Context (language use), 02 engineering and technology, Nuclear reactor, 01 natural sciences, law.invention, Nuclear physics, 0205 materials engineering, Deuterium, law, Nuclear fission, 0103 physical sciences, Neutron source, Neutron, Nuclear Experiment
Abstract

There is a worldwide growing interest for small-scale and reduced-cost neutron sources not based on nuclear fission. High-intensity proton or deuteron beams impinging on light materials could be used to produce such neutron sources with intensities or brightness comparable to nuclear reactor for dedicated experiments. To develop such technologies several key technological issues have to be addressed. Among them the neutron production and the maximization of the neutron extraction and transport to the instrument is a key parameter for the design of high-brightness sources adapted for the required application. This issue have to be addressed with validated and predictive Monte-Carlo simulations. In this paper we present preliminary results on the use of Geant4 in the context of Compact Accelerator based Neutron Source (CANS) developments.

Published
2017

41. Neutron imaging investigation of fossil woods: non-destructive characterization of microstructure and detection of in situ changes as occurring in museum cabinets

Author

Pierre Levitz, Laurent J. Michot, Natalie Malikova, Giliane P. Odin, Véronique Rouchon, Frédéric Ott, Centre de Recherche sur la Conservation (CRC ), Muséum national d'Histoire naturelle (MNHN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture et de la Communication (MCC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay

Subjects
In situ, [SDV]Life Sciences [q-bio], Neutron imaging, Mineralogy, 02 engineering and technology, Hydrogen content, 010502 geochemistry & geophysics, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, Characterization (materials science), Paleontology, lcsh:Paleontology, [SDU]Sciences of the Universe [physics], Non destructive, Water diffusion, 0210 nano-technology, lcsh:QE701-760, Time range, Geology, 0105 earth and related environmental sciences
Abstract

This paper discusses the applicability of neutron imaging techniques for probing the internal microstructure of several fossil woods upon wetting and drying, two phenomena occurring in museum cabinets and endangering the fossil woods. Investigations were carried out using lignites (fossil woods) from two French localities (Rivecourt, Parisian Basin, Oise – Paleogene; Angeac, Aquitanian Basin, Charente – Cretaceous), which present different macroscopic behavior upon drying. Thanks to the high sensitivity of neutrons to hydrogen content, it was possible to track water diffusion through 3 mm thick samples and to follow in situ changes related to either supply or withdrawal of water without any special preparation and in a relevant time range (from 1 min to a few hours). Classical image analysis allows discriminating between the behavior of the two fossil woods with regard to their interaction with water. Further analysis based on a Fourier transform of projection images provides additional information regarding the existence of large pores in one of the samples. Differences in pore network and internal structures have important mechanical consequences as one of the samples retains its integrity upon drying, whereas the other one shatters into pieces. A better understanding of the underlying processes will clearly require multi-scale analyses, using additional techniques that could probe the materials at a lower scale. Such a combination of multi-scale analyses should provide valuable information for a better conservation of wood remnants, which is crucial for both paleobotanical research and museum exhibits.

Published
2017
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42. Nanostructuration of Cr/Si layers induced by ion beam mixing

Author

Gianguido Baldinozzi, Laurence Luneville, Cyrile Deranlot, Ludovic Largeau, Frédéric Ott, Nathalie Moncoffre, David Simeone, Yves Serruys, Laboratoire Structures, Propriétés et Modélisation des solides (SPMS), Institut de Chimie du CNRS (INC)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Département de Modélisation des Systèmes et Structures (DM2S), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Service de recherches de métallurgie physique (SRMP), Département des Matériaux pour le Nucléaire (DMN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Laboratoire d'Analyse Microstructurale des Matériaux (LA2M), Service des Recherches Métallurgiques Appliquées (SRMA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Département des Matériaux pour le Nucléaire (DMN), RTRA Triangle de la physique, 2011-074T, INSTRUMAT, THALES [France]-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Ion beam analysis, Ion beam mixing, business.industry, Analytical chemistry, 02 engineering and technology, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, Focused ion beam, X-ray reflectivity, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Microelectronics, Irradiation, 010306 general physics, 0210 nano-technology, Reflectometry, business
Abstract

This work clearly demonstrates that the X Ray Reflectometry technique (XRR), extensively used to assess the quality of microelectronic devices can be a useful tool to study the first stages of ion beam mixing. This technique allows measuring the evolution of the Si concentration profile in irradiated Cr/Si layers. From the analysis of the XRR profiles, it clearly appears that the Si profile cannot be described by a simple error function.

Published
2013
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43. High temperature structural and magnetic properties of cobalt nanorods

Author

Fatih Zighem, Kahina Ait Atmane, Frédéric Ott, Jérémie Margueritat, Jean-Yves Piquemal, Mona Ibrahim, Grégory Chaboussant, Guillaume Viau, Yaghoub Soumare, Rym Boubekri, Frédéric Schoenstein, Noureddine Jouini, T. Maurer, Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Université Paris Diderot - Paris 7 (UPD7)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences des Procédés et des Matériaux (LSPM), Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Cité (USPC)-Institut Galilée-Université Paris 13 (UP13), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris 13 (UP13)-Institut Galilée-Université Sorbonne Paris Cité (USPC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, thermal treatments, Analytical chemistry, FOS: Physical sciences, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, Inorganic Chemistry, Nuclear magnetic resonance, law, Materials Chemistry, Texture (crystalline), Physical and Theoretical Chemistry, polyol process, Anisotropy, Condensed Matter - Materials Science, permanent magnets, Materials Science (cond-mat.mtrl-sci), [CHIM.MATE]Chemical Sciences/Material chemistry, Coercivity, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Magnetocrystalline anisotropy, cobalt, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, SQUID, Magnet, X-ray crystallography, Ceramics and Composites, Nanorod, nanorods, 0210 nano-technology
Abstract

We present in this paper the structural and magnetic properties of high aspect ratio Co nanoparticles (~10) at high temperatures (up to 623 K) using in situ X ray diffraction (XRD) and SQUID characterizations. We show that the anisotropic shapes, the structural and texture properties are preserved up to 500 K. The coercivity can be modelled by u0Hc=2(Kmc+Kshape)/Ms with Kmc the magnetocrystalline anisotropy constant, Kshape the shape anisotropy constant and Ms the saturation magnetization. Hc decreases linearly when the temperature is increased due to the loss of the Co magnetocrystalline anisotropy contribution. At 500K, 50% of the room temperature coercivity is preserved corresponding to the shape anisotropy contribution only. We show that the coercivity drop is reversible in the range 300 - 500 K in good agreement with the absence of particle alteration. Above 525 K, the magnetic properties are irreversibly altered either by sintering or by oxidation., 8 pages, 7 figures, submitted to Journal of Solid State Chemistry

Published
2013
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44. Neutron Imaging of Meat during Cooking

Author

Simone Scussat, Philippe Cayot, Camille Loupiac, Sylvain Desert, Frédéric Ott, Arnaud Hélary, Procédés Alimentaires et Physico-Chimie (PAPC), Procédés Alimentaires et Microbiologiques (PAM), Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Vitagora, Cap Digital, Imaginove, Aquimer, Microtechniques, Agrimip - French state, Franche-Comte Council as part of Programme d'Investissements d'Avenir run by Bpifrance, Procédés Alimentaires et Physico-Chimie ( PAPC ), Procédés Alimentaires et Microbiologiques ( PAM ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Laboratoire Léon Brillouin ( LLB - UMR 12 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
0301 basic medicine, Nmr relaxometry, Materials science, Meat, Sample (material), Biophysics, Water migration, Structural-changes, Mineralogy, Bioengineering, tomography, Applied Microbiology and Biotechnology, Analytical Chemistry, 03 medical and health sciences, 0404 agricultural biotechnology, Differential scanning calorimetry, [SDV.IDA]Life Sciences [q-bio]/Food engineering, Neutron, Food science, Cooking, Shrinkage, 030109 nutrition & dietetics, Contraction, Dehydration, Attenuation, Neutron imaging, [ SDV.IDA ] Life Sciences [q-bio]/Food engineering, technology, industry, and agriculture, food and beverages, Proteins, 04 agricultural and veterinary sciences, 040401 food science, Heat, Denaturation, Muscle, Food Science
Abstract

International audience; Neutron imaging was used to follow the impact of cooking on beef meat. During online cooking, the cartography realised on image collected shows neutron attenuation per zone. Some data points were taken on the edge to highlight higher attenuation variations because of "microscopic" shrinkage of the meat at 70 degrees C. Some others points were taken in the centre of the sample, which first showed smaller decreases at 75 degrees C and then an increase around 80 degrees C. These smaller attenuation variations are possibly linked to denaturation of connective tissue which in turn influenced meat microstructure allowing the release of entrapped water and increase the thickness of the sample.

Published
2016
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45. Temperature Study of the Antiferromagnetic Coupling at the Interface of La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ and SrRuO$_{3}$ Bilayers

Author

Frédéric Ott, Claude Fermon, P. Gogol, Myriam Pannetier-Lecoeur, Ruben Guerrero, Ph Lecoeur, A. Solignac, Thomas Maroutian, Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut d'électronique fondamentale (IEF), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Materials science, Condensed matter physics, Field (physics), Bilayer, 02 engineering and technology, Coercivity, 021001 nanoscience & nanotechnology, 01 natural sciences, Antiferromagnetic coupling, Electronic, Optical and Magnetic Materials, Magnetization, Exchange bias, Ferromagnetism, 0103 physical sciences, Antiferromagnetism, Electrical and Electronic Engineering, 010306 general physics, 0210 nano-technology
Abstract

International audience; We have studied the antiferromagnetic coupling at the interface of the La0.7Sr0.3MnO3/SrRuO3 bilayer as function of temperature. We measured the La0.7Sr0.3MnO3 magnetization reversal while the SrRuO3 magnetization is blocked due to a field cooled procedure and because of its high coercive field. Even if in this system, the La0.7Sr0.3MnO3 magnetization cycle may be explained by two exchange couplings which coexist up to 120 K, the exchange bias and the coercive field from 5 K to 300 K have a similar behavior from some ferromagnetic/antiferromagnetic...

Published
2012
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46. Data representations of Zeeman spatial beam splitting in polarized neutron reflectometry

Author

Frédéric Ott, S. V. Kozhevnikov, and Florin Radu

Subjects
Zeeman effect, business.industry, Chemistry, Zero field splitting, Refraction, Molecular physics, General Biochemistry, Genetics and Molecular Biology, Electromagnetic induction, symbols.namesake, Optics, Ferromagnetism, symbols, Neutron, Zeeman energy, Neutron reflectometry, business
Abstract

The different Zeeman beam-splitting effects in neutron reflectivity experiments in reflection and refraction are discussed. Different possible representations of the experimental Zeeman splitting data in various coordinate systems are investigated. Some of these representations are useful to unambiguously identify the off-specular splitting arising from Zeeman energy and discriminate it from the usual diffuse scattering. Some representations are more suited for the direct extraction of quantitative information about the systems by using the Zeeman splitting effect. The Zeeman splitting can thus be used as a tool rather than being treated as a parasitic effect. Parameters such as the optical and magnetic potentials of buried layers can be directly extracted. The magnetic induction in demagnetized samples can also be probed. These representative characteristics are illustrated by experimental data measured on different systems. In thick AlSiFe films (20 µm), the magnetic induction is determined at the top and bottom interfaces. In thin Co layers (250 nm), the magnetic induction of ferromagnetic domains in the demagnetized state is evaluated.

Published
2012
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47. Neutron Scattering on Magnetic Thin Films

Author

A. M. Bataille and Frédéric Ott

Subjects
Nuclear and High Energy Physics, Materials science, business.industry, Analytical chemistry, Neutron scattering, Inductive coupling, Atomic and Molecular Physics, and Optics, Metal, Condensed Matter::Materials Science, Nuclear magnetic resonance, Semiconductor, Ferromagnetism, Transition metal, visual_art, visual_art.visual_art_medium, Thin film, business, Deposition (law)
Abstract

During the early 80s, advanced techniques for the deposition of ultra-thin metal films were developed. This led to the fabrication of new artificial materials consisting of different materials stacked in thin sandwiches (hetero-structures). The combination of these different types of materials gave rise to new physical phenomena. The first new phenomenon to be probed was the magnetic exchange coupling in super-lattices. It appeared that magnetic layers separated by non magnetic spacer layers can be magnetically coupled. The coupling can be ferromagnetic, anti-ferromagnetic or more complex (quadratic or even helical). The coupling can also change sign (from ferro to anti-ferro) as a function of the spacer layer thickness. Such phenomena were observed in rare-earth super-lattices (Gd/Y, Dy/Y, Gd/Dy, Ho/Y), transition metals super-lattices (Fe/Cr, Co/Cu, Fe/V, Co/Ru), and mixing of semiconductors and metals (Fe/Si, Fe/Ge). The field is still expanding as new systems are being synthesized, especially with mag...

Published
2011
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48. Magnetic layered structure for the production of polarized neutron microbeams

Author

Frédéric Ott, A. Rühm, S. V. Kozhevnikov, Janos Major, and N. K. Pleshanov

Subjects
Permalloy, Materials science, business.industry, Physics::Optics, Neutron radiation, Condensed Matter Physics, Collimated light, Electronic, Optical and Magnetic Materials, law.invention, Optics, law, Neutron source, Neutron, Neutron reflectometry, Electrical and Electronic Engineering, business, Waveguide, Beam (structure)
Abstract

A neutron waveguide is a three-layer structure in which a guiding layer with low optical potential is placed between two cladding layers with high optical potential. Under proper operation conditions, the neutron density is resonantly enhanced inside the guiding layer. In our experimental scheme, the neutron beam enters through the surface of the top layer at glancing angle and goes out from the edge of the guiding layer, with an angular distribution corresponding to Fraunhofer diffraction from a narrow slit. The incident neutron beam is relatively wide (0.1 mm) and highly collimated (0.01°). The outgoing sub-micron beam is extremely narrow at the outlet (0.1 μm) and more divergent (0.1°). So far only the production of unpolarized sub-micron neutron beams has been reported. Here we present first experiments on polarized sub-micron neutron beams. For these studies a polarized incident beam was used and two types of magnetic waveguides were investigated: a polarizing magnetic waveguide Fe(20 nm)/Cu(140 nm)/Fe(50 nm)//glass and a non-polarizing magnetic waveguide Py(10 nm)/Al(140 nm)/Py(50 nm)//glass (Py is permalloy). The waveguide samples were characterized by polarized neutron reflectometry.

Published
2011
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49. Saclay Compact Accelerator-driven Neutron Sources (SCANS)

Author

A. Letourneau, Frédéric Ott, Alain Menelle, H.N. Tran, Anthony Marchix, Jérôme Schwindling, and Nicolas Chauvin

Subjects
Physics, History, Proton, Fission, Nuclear engineering, Nuclear Theory, chemistry.chemical_element, Peak current, Neutron scattering, Computer Science Applications, Education, chemistry, Physics::Accelerator Physics, Neutron source, Neutron, Beryllium, Nuclear Experiment, Beam (structure)
Abstract

For next decade, the European neutron scattering community will face of important changes, as many facilities will close, strictly fission-based sources. This statement mainly concerns France with the planned closure of Orphee and ILL. At CEA-Saclay, the project SONATE has been launched in order to provide a high intensity neutron source in Saclay site, this project is based on Compact Accelerator-driven Neutron Sources technology coupled to high-intensity beams. The goal of SONATE is to develop a 50 kW target, aiming to produce at least a neutron yield of 1013 s-1 in pulse mode with a peak current of 100 mA. We have investigated in this document the best combinations of beam/target which would lead to this substantial neutron yields. Further investigations and tests have to be carry out, especially due to sparse data on thick target and such low-energy beams considered in this document. An intermediate step to the SONATE project is under test and development, called IPHI-NEUTRON, which would lead to provide a small-size neutron facility mainly devoted to neutron imagery for industry. This step is based on the existing 3 MeV proton beam, named IPHI. Best target candidates are Lithium and Beryllium, leading respectively to a neutron yield of about 2.1013 s-1 and 4.1012 s-1.

Published
2018
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50. Validation of Geant4 simulation tool for low energy proton induced reactions

Author

A. Letourneau, Alain Menelle, Frédéric Ott, Jérôme Schwindling, Nicolas Chauvin, H.N. Tran, and Anthony Marchix

Subjects
Nuclear physics, History, Materials science, Low energy, Proton, 010308 nuclear & particles physics, 0103 physical sciences, 010306 general physics, 01 natural sciences, Computer Science Applications, Education
Published
2018
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