Energy-resolved neutron imaging with glass gas electron multiplier and dynamic time-over-threshold method

Energy-resolved neutron imaging with pulsed neutron source provides quantitative neutron imaging techniques such as Bragg-edge imaging, resonance absorption imaging, and polarized neutron imaging. Micro-pattern gaseous detectors (MPGDs) such as gas electron multipliers (GEMs) are widely used in neutron detection. In this research, we will report on the first demonstration of energy-resolved neutron imaging with a glass gas electron multiplier (G-GEM) and the dynamic time-over-threshold (dToT) signal processing method. We successfully performed energy-resolved neutron imaging at J-PARC MLF by measuring incident position and the Time-of-Flight (TOF) of each neutron simultaneously.

New Methods, New Opportunities. Recent Advances in Archaeological Science and their Application in Arms and Armour Studies

The jubilee of Professor Andrzej Nadolski and Professor Marian Głosek is an excellent opportunity for discussing some most recent methods of technological analyses in archaeology and their applications in arms and armour studies. New opportunities are offered by Computed Tomography (CT) and by Neutron Imaging (NI). The latter is insensitive to material density; therefore details that are not detectable by X-ray or CT can be seen in NI images. A considerable progress has also been made in the field of radiocarbon dating. Yet another field are analyses of the chemical composition of smelting slag and slag inclusions in ferrous artefacts. Such analyses can be used for identification of smelting processes, as well as for provenance studies. These take a number of variables into consideration (major and trace elements, as well as isotopic ratios). What seems to be especially promising in provenance studies are isotopes of osmium (Os).

Study of Structural Characteristics of Ancient Bricks With Neutron Radiography Facility at BTRR

Neutron radiography (NR) has been applied successfully to investigate different types of building materials, rock samples, sculptures, statues or monuments for since long. The utilization of neutron imaging for non-invasive investigations of cultural heritage objects is demonstrated on the example of ancient bricks found in Mahasthangarh and Sonargaon, two key archaeological sites in Bangladesh. The visualization of the internal structure of different brick samples, by means of Neutron Radiography (NR), has been experimented using the BTRR research reactor in Bangladesh - the only neutron imaging facility available in Bangladesh for R D purposes. Manufacturing building materials have become a very good option for business in developing countries like Bangladesh. Among the non-destructive testing (NDT) techniques, neutron radiography is the most common procedure to identify light and organic materials, homogeneity, any inclusion or voids or cracks etc. inside the structure. The radiographic images in a dry condition for individual samples have been investigated. The image analysis was performed using ImageJ software and texture features were extracted using gray level co-occurrence matrix implemented by MATLAB for acquiring qualitative and quantitative information from this inspection technique at a high level of accuracy. The results obtained by neutron imaging provide the statement that the brick sample from Mahasthangarh is more homogeneous inside.

Characterisation of Single-Phase Fluid-Flow Heterogeneity Due to Localised Deformation in a Porous Rock Using Rapid Neutron Tomography

The behaviour of subsurface-reservoir porous rocks is a central topic in the resource engineering industry and has relevant applications in hydrocarbon, water production, and CO2 sequestration. One of the key open issues is the effect of deformation on the hydraulic properties of the host rock and, specifically, in saturated environments. This paper presents a novel full-field data set describing the hydro-mechanical properties of porous geomaterials through in situ neutron and X-ray tomography. The use of high-performance neutron imaging facilities such as CONRAD-2 (Helmholtz-Zentrum Berlin) allows the tracking of the fluid front in saturated samples, making use of the differential neutron contrast between “normal” water and heavy water. To quantify the local hydro-mechanical coupling, we applied a number of existing image analysis algorithms and developed an array of bespoke methods to track the water front and calculate the 3D speed maps. The experimental campaign performed revealed that the pressure-driven flow speed decreases, in saturated samples, in the presence of pre-existing low porosity heterogeneities and compactant shear-bands. Furthermore, the observed complex mechanical behaviour of the samples and the associated fluid flow highlight the necessity for 3D imaging and analysis.

A comparative study of promising filter materials for neutron imaging facilities

The effect of sapphire and bismuth single-crystal filters and their combinations on the quality of neutron radiographic images and neutron tomography data has been studied. The parameters of the contrast of the neutron image were analyzed depending on the monocrystalline filters. Neutron transmission spectra were obtained for sapphire and bismuth single crystals. Additionally, the effect of filters on the overall intensity of the thermal neutron beam and the background of gamma-rays was investigated. Based on the obtained data, we assume that a single-crystal sapphire filter can be most effectively used for radiographic and tomographic installations using thermal neutrons.

Sparse-View Neutron CT Reconstruction Using a Modified Weighted Total Difference Minimization Method

Indirect neutron imaging is an effective method for nondestructive testing of spent nuclear fuel elements. Considering the difficulty of obtaining experimental data in a high-radiation environment and the characteristic of high noise of neutron images, it is difficult to use the traditional FBP algorithm to recover the complete information of the sample based on the limited projection data. Therefore, it is necessary to develop the sparse-view CT reconstruction algorithm for indirect neutron imaging. In order to improve the quality of the reconstruction image, an iterative reconstruction method combining SIRT, MRP, and WTDM regularization is proposed. The reconstruction results obtained by using the proposed method on simulated data and actual neutron projection data are compared with the results of four other algorithms (FBP, SIRT, SIRT-TV, and SIRT-WTDM). The experimental results show that the SIRT-MWTDM algorithm has great advantages in both objective evaluation index and subjective observation in the reconstruction image of simulated data and neutron projection data.