High Current Compact Accelerator-driven Neutron Sources (HiCANS) have recently emerged as a possible solution to the drop in neutron provision in Europe due to the closure of several research reactors. Within this new trend, the Laboratoire Léon Brillouin (LLB) is currently assessing the performance of neutron techniques around this novel type of source. HERMES is a time-of-flight horizontal reflectometer that was operated by the LLB at the ORPHEE reactor until 2019 and was dedicated to soft matter studies. Through a collaboration with the Jülich Centre for Neutron Science, HERMES was installed in 2022 at the JULIC Neutron Platform (JNP) at the Forschungszentrum Jülich. This platform is able to deliver neutron pulses in the 100 μs - 2 s range and is very well suited to evaluate the feasibility of reflectivity experiments at a HiCANS. Since its installation and first tests in 2022, several improvements have been implemented at HERMES. Our current goal is to perform reflectivity experiments with large neutron mirrors as a proof of concept, as the flux at the JNP is several orders of magnitude lower than the original ORPHEE flux or the one expected at a HiCANS. Nevertheless, Monte Carlo simulations show that an instrument as HERMES operating at a HiCANS could match the performance of similar instruments at research reactors and spallation sources.

Low energy accelerator-driven neutron sources are intrinsically limited by the peak flux they can provide. A possible way to increase the total brilliance of the source is to increase the neutron pulse length. However, the efficient use of time-of-flight techniques on long pulse sources is non trivial. ESS is building long instruments (up to 150 m) to be able to fully exploit the long pulse structure. Such a solution cannot be reasonably implemented on CANS or HiCANS, essentially for cost reasons. We are thus investigating the possibilities of implementing statistical time modulation on a diffraction instrument to be able to use very long pulse structures. We present Monte-Carlo (MC) simulations using statistical time modulation and propose the design of a powder diffractometer, which could be installed on the long pulse target station of the ICONE HiCANS source. These MC simulations allow anticipating the difficulties which would be encountered if such an instrument would be built.

In this contribution we showcase the use of OpenMC for the validation and optimization of a low dimensional cold neutron moderator for the ICONE project. An overview of our simulation strategy is given and initial results for an optimized layout of a low-dimensional cold neutron moderator are presented. The increase in neutron emission brightness when using a low-dimensional geometry is verified.

In the last decades, neutron imaging facilities have implemented systems such as imaging plates and CCD or sCMOS cameras coupled to a scintillator screen [1]. However, for some applications, such as detection of micro cracks in large-size metallic or organic materials such as pyrotechnic equipment, these methods have disadvantages, mostly related to their small field of view when high resolutions are required. On the other hand, the use of silver radiographic films, although an old technology restricted to static 2D imaging, allows observing details with very good spatial resolution (<50 µm) and over very large areas (30x30cm²), which compensates for their low efficiency. Since there is currently no technology that fulfills these needs, radiographic films were used on the Orphée reactor at the CEA Saclay until its shutdown in 2019. The CEA aims at potentially continuing the previous historical radiography activities on a new French HiCANS source, the ICONE project. Within this context, we aim at comparing radiographic films and other technologies. Hence radiographies were taken with films at PSI/SINQ on the NEUTRA beam line (with thermal neutrons, which will probably will be used at the ICONE facility) in order to compare them with measurements on the same objects taken at the Orphée nuclear reactor (with cold neutrons). Images were obtained with different neutron energies, different L/D and different fluence levels. High-resolution digitalization of the film was performed for quantitative analysis. We compared these images to those obtained with imaging plates or CCD cameras. A study of the quality and the statistics of the images after digitalization was done in order to quantify the evolutions of the dynamic range and the spatial resolution. We also aim at evaluating the effect of thermal energies vs cold energies. With these results, it could be determined if the usage of films can complement modern neutron imaging methods to fulfil specific requirements.

HERMES is a time-of-flight reflectometer that operated at the Orphée reactor until 2019. In 2022, HERMES was installed at the JULIC (Jülich Light Ion Cyclotron) Neutron Platform as part of a collaboration between the Laboratoire Léon Brillouin and the Jülich Centre for Neutron Science. The main goal of the current setup is to probe the viability of neutron instrumentation at a High Current Compact Accelerator-driven Neutron Source (HiCANS). As the flux at the JULIC neutron platform is several orders of magnitude lower than the original Orphée flux or the expected flux for a HiCANS, our current objective is to perform reflectivity experiments with supermirrors as a proof of concept. Nevertheless, Monte-Carlo simulations showed that the HERMES instrument’s performance at a HiCANS such as HBS or ICONE could match that of reflectometry instruments operating at research reactors or spallation sources. An experiment with a supermirror carried out in December 2022 allowed us to preliminary prove the feasibility of this kind of experiments at an accelerator-driven neutron source.

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.

High Current Accelerator driven Neutron Sources (HiCANS) are a cost-efficient alternative for future large scale neutron facilities. They excel in transforming neutrons released by the primary nuclear reaction into a spectral range usable for applications. In particular, the cost of a target station represents only a minor fraction of the overall construction cost due to the lower energy of the primary neutrons, which requires less shielding. They can be designed to provide optimized pulse and spectral properties for applications in neutron scattering, analytics and imaging experiments. For the High Brilliance neutron Source (HBS) project at Forschungszentrum Jülich, we have developed a modular design that meets the radiation protection requirements while providing sufficient space in its core to adapt the target-moderator-reflector assembly to the different applications. In the following, we present the basic target station design which will be used at HBS for three different realizations with their own instrument suite. All relevant components have been designed, built and tested at the JULIC Neutron Platform which has produced neutrons since December 12th 2022. The simulated performance of a target station shows that the brightnesses of the moderators are in the range of modern research reactors and sub-MW power spallation sources.

We present the ICONE project which proposes to build a HiCANS source in France. The aim of the ICONE project is to be able to provide the French neutron user community sufficient instrumental capacity to continue performing neutron scattering experiments for their research programs. The baseline goal is to offer performances equivalent to a medium power research reactor or spallation source (such as Orphée or ISIS). We consider that such a machine would fulfil the needs of at least two-thirds of the users which not require ultimate performances but simply beam-time to perform their experiments. We also describe the experimental work ongoing at Saclay around the various technologies necessary to build a HiCANS.

The High Brilliance neutron Source (HBS) is a project for a next generation neutron research facility, based on new concepts and recent technological advancements. As elementary processes it uses neither fission nor spallation, but instead low energy nuclear reactions in a very compact Target-ModeratorReflector (TMR) assembly. Our facility design results in very efficient production of neutron beams with high brightness. Key features of HBS are: (i) very competitive instrument performance, (ii) comparatively low construction and operation costs, (iii) resilience, (iv) sustainability, (v) flexibility, (vi) accessibility and (vii) scalability. Here we present the basic layout of the facility, elaborate on the mentioned key features and report on the commissioning of a small test setup.

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.

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.

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.

Compact accelerator-based neutron sources (CANS) represent a growing technology to provide neutrons in many areas of research and applications. Based on nuclear processes initiated by low energy proton or deuteron beams or the nuclear photo effect using electron beams, very compact neutron sources have been designed and installed at universities, research institutes, and industrial sites accross the globe. These small sources have provided continuous impact in fundamental nuclear physics as well as in material sciences, engineering, metrology or health. In most recent years partly driven by the advent of reactor based neutron sources and the desire for local and mobile neutron sources and partly by progress in high current proton accelerator systems, efforts are increasing to develop, design and construct very powerful CANS. One goal of these efforts is to provide future midand large-scale neutron sources complementary to spallation and reactor based sources, while another is to provide local services for industry or health e.g. as neutron imaging services or with boron neutron capture therapy to fight cancer. The Union for Compact Accelerator-driven Neutron Sources (UCANS) is organizing regular meetings to discuss the state of the art and developments on this topic. The UCANS9 conference was planned to be held in Wako, Japan in November 2020. Due to the global coronavirus outbreak the conference could not happen and was postponed to a future date in 2021. As an intermediate activity a web-based meeting was organized termed UCANS-web Conference and held from Nov. 30 to Dec. 3 2020 with a world-wide attendance of many scientists and researchers. The virtual conference covered a very wide range of topics on most aspects of compact sources, accelerators, targets, moderators, detectors, neutron scattering, radiography, isotope and nuclear data, medical applications as documented at the conference website (ucans-web.org). The diverse and varied presentations and discussions at this virtual meeting inspired the participants and organizers to publish presented work within a proceedings volume in the Journal of Neutron Research. The present contributions deal with basic nuclear data evaluation by improved scattering kernels, the development of versatile beam monitoring and multiplexing systems as well as the design and configuration of optimized target-moderator combinations to improve neutron flux. They further present novel instrumentation concepts and the plans and outlines for novel CANS facilities. Although these articles represent only a fraction of all of the presented contributions within the UCANS-web Conference, they demonstrate the progress and state-of-the-art in this fast-emerging field. Upcoming conferences, workshops and UCANS meetings will show further progress and developments and the present proceedings will support all these discussions and activities to develop and optimize CANS.

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.

Zirconium-based claddings with an outer chromium coating resistant to corrosion are studied and developed as an evolutionary Enhanced Accident Tolerant Fuel (E-ATF) concept for light water reactors. However, 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) CrxCy 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 degrees C on Zircaloy-4 clad prototypes with a 5-20 mu m-thick CrxCy 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 degrees C, on short inner and/or outer-coated clad segments. Finally, PostQuench (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 CrxCy 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 degrees 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 innercoated material, related to lower oxygen and hydrogen uptakes of the substrate. (c) 2021ElsevierB.V. Allrightsreserved.

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.

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...

We describe the Compact Accelerator-based Neutron Source SONATE which we are aiming for to replace the closed 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.

The method of neutron imaging was adopted to map the concentration evolution of aqueous paramagnetic Gd(NO3)(3) solutions. Magnetic manipulation of the paramagnetic liquid within a miscible nonmagnetic liquid is possible by countering density-difference driven convection. The formation of salt fingers caused by double-diffusive convection in a liquid-liquid system of Gd(NO3)(3) and Y(NO3)(3) solutions can be prevented by the magnetic field gradient force.

Hypothesis: Colloidal silica dispersions dried under controlled conditions form solid gels that display mechanical properties similar to those observed in several practical processes. An understanding of their structural characteristics and liquid flow properties can therefore help establish these gels as an alternative family of model materials to study practical porous systems. Experiments: Neutron radiography is a non-destructive technique well-adapted to study hydrogen-rich domains in porous materials due to the high attenuation power of hydrogen. We apply this technique to study gels prepared from silica nanoparticles of radii 5-40 nm. Findings: The water content in the gels have been quantified and different types of porosities have been determined: total porosity, effective porosity that contributes to liquid flow, and residual porosity that contains bound residual water. This residual water increases with decrease in particle size and constitutes an important fraction of the gel. The dynamics of water imbibition follows a root t law, from which the effective pore size and permeability are evaluated. We highlight the role of particle size on water retention, on particle organization and its impact on mechanical resistance. Quantitative analysis of the propagating liquid front shows front broadening that suggests elongated pores with reduced correlated liquid menisci. (C) 2020 Elsevier Inc. All rights reserved.