NeXT-Grenoble, the Neutron and X-ray tomograph in Grenoble

Tengattini, Alessandro; Lenoir, Nicolas; Andò, Edward; Giroud, Benjamin; Atkins, Duncan; Beaucour, J.; Viggiani, Gioacchino

doi:10.1016/j.nima.2020.163939

Cited by 91 publications

(66 citation statements)

References 40 publications

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“…In the lab (and presumably on site) the exposed, drying face of the clay-rock is rapidly wetted by the free water of the fresh concrete. To gain some insight into the causes of this phenomenon, a number of in-situ wetting experiments have been carried out with high-speed lab x-ray tomography (in Laboratoire 3SR) and neutron radiography (at the ILL instrument D50-tomo or "NeXT", an instrument that has recently come online in Grenoble [16]).…”

Section: Many Authors Have Studied the Effect Of Drying And Wetting Cmentioning

confidence: 99%

Liquid water uptake in unconfined Callovo Oxfordian clay-rock studied with neutron and X-ray imaging

et al. 2018

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The Callovo Oxfordian clay-rock (COx) is studied in France for the disposal of radioactive waste, because of its extremely low permeability. This host rock is governed by a hydromechanical coupling of high complexity. This paper presents an experimental study into the mechanisms of water uptake in small, unconfined, prismatic specimens of COx, motivated by the comprehension of cracking observed during concrete/COx interface sample preparation. Water uptake is monitored using both x-ray tomography and neutron radiography, the combination of these imaging techniques allowing material deformation and water arrival to be quantified respectively. Given the speed of water entry and crack propagation, relatively fast imaging is required: 5 minute x-ray tomographies and ten-second neutron radiographies are used. In this study, pairs of similar COx samples from the same core are tested separately with each imaging technique. Two different orientations with respect to the core are also investigated. Analysis of the resulting images yields with micro-and macro-scale insights into hydro-mechanical mechanisms to be obtained. This allows the cracking to be interpreted as a rapid breakdown in capillary suction (supposed large both to drying and rebound from in-situ stress state) due to water arrival, which in turn causes a loss of effective stress, allowing cracks to propagate with ease, which in turn deliver water further into the material.

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Section: Many Authors Have Studied the Effect Of Drying And Wetting Cmentioning

confidence: 99%

Liquid water uptake in unconfined Callovo Oxfordian clay-rock studied with neutron and X-ray imaging

et al. 2018

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“…Series of flow-through experiments have been performed at two different neutron sources: the D50 beamline (Tengattini et al, 2017) of the Institut Laue-Langevin (Grenoble, France) and the ICON beamline of SINQ (Kaestner et al, 2011a) at the Paul Scherrer Institut (Villigen, Switzerland). The first one is a fission type source where neutron flux can be as high as 1.5 10 15 n/cm 2 /s, while the second one is a spallation type source with a flux as high as 10 14 n/cm 2 /s.…”

Section: Methodsmentioning

confidence: 99%

Neutron Imaging of Cadmium Sorption and Transport in Porous Rocks

et al. 2019

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Understanding fluid flow in rocks is crucial to quantify many natural processes such as ground water flow and naturally triggered seismicity, as well as engineering questions such as displacement of contaminants, the eligibility of subsurface waste storage, geothermal energy usage, oil and gas recovery and artificially induced seismicity. Two key parameters that control the variability of fluid flow and the movement of dissolved chemical species are (i) the local hydraulic conductivity, and (ii) the local sorption properties of the dissolved chemical species by the solid matrix. These parameters can be constrained through tomography imaging of rock samples subjected to fluid injection under constrained flow rate and pressure. The neutron imaging technique is ideal to explore fluid localization in porous materials due to the high but variable sensitivity of neutrons to the different hydrogen isotopes. However, until recently, this technique was underused in geology because of its large acquisition time. With the improved acquisition times of newly setup neutron beamlines, it has become easier to study fluid flow. In the current set of experiments, we demonstrate the feasibility of in-situ 2D and 3D time-lapse neutron imaging of fluid and pollutant percolation in rocks, in particular that of cadmium salt. Cadmium is a hazardous compound that is found in many electronic devices, including batteries and is a common contaminant in soil and groundwater. It also exhibits higher contrast in neutron attenuation with respect to heavy water, and is therefore an ideal tracer. Time-lapse 2D radiographies and 3D neutron tomographies of the samples were acquired on two neutron beamlines (ILL, France and SINQ, Switzerland). We performed two sets of experiments, imbibition and injection experiments, where we imaged in-situ flow properties, such as local permeability and interactions between cadmium and the solid rock matrix. Our results indicate that even within these cm-scale porous rocks, cadmium transport follows preferential pathways, and locally interacts within the limestone samples. Our results demonstrate that the use of neutron imaging provides additional insights on subsurface transport of pollutants.

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“…ILL eventually stopped neutron imaging but FRM-2 and HMI Germany with PSI Switzerland in particular, continued to develop the technique. Only recently has ILL built a new world class neutron imaging station, on a high resolution and high flux cold guide [3]. ILL did however, continue to develop CCD cameras for sample alignment and diffraction.…”

Section: The Origins Of Neutron Cameras and The Advantages Of Simplimentioning

confidence: 99%