Neutron radiography activity in the european program cost 524: Neutron imaging techniques

2001 ◽  
Author(s):  
P. Chirco
2009 ◽  
Author(s):  
T. Materna ◽  
Jan Jolie ◽  
Andreas Zilges ◽  
Nigel Warr ◽  
Andrey Blazhev ◽  
...  

Author(s):  
Andrew T. Boothroyd

The description of neutron optical phenomena within the framework of dynamical diffraction theory is described. The coherent wave and optical potential are introduced, and an expression for the complex neutron refractive index in terms of the scattering length density and attenuation coefficient is obtained. The extension to magnetic media and polarized neutrons is covered. Neutron reflectivity is defined, and the wavevector dependence of the reflectivity profile is derived by a transfer matrix method and an optical method. Exact results are compared with the Born approximation. The technique of neutron imaging is described, including neutron radiography and computed tomography. Several optical phenomena that occur in Bragg diffraction from near-perfect crystals, including Pendellösung oscillations, and primary and secondary extinction.


Instruments ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 32 ◽  
Author(s):  
Federica Mingrone ◽  
Marco Calviani ◽  
Claudio Torregrosa Martin ◽  
Oliver Aberle ◽  
Michael Bacak ◽  
...  

A neutron radiography testing station has been developed exploiting the neutron beam of CERN’s n_TOF Experimental Area 2, located at the shortest distance to the neutron producing-target. The characteristics of the n_TOF neutron beam for the imaging setup are presented in this paper, together with the obtained experimental results. The results focused on the testing of several particle producing targets, including a spent antiproton production targets as well as targets from two different HiRadMat’s experiments. The possible developments of neutron imaging capabilities of the n_TOF facility in terms of detection-systems and beam-line upgrades are as well outlined.


2013 ◽  
Vol 92 (2-3) ◽  
pp. 177-180 ◽  
Author(s):  
A.S. Schulp ◽  
R. Schouten ◽  
L. Metten ◽  
A. van de Sande ◽  
A. Bontenbal

AbstractIn the conservation of fragile fossil bone material, impregnation by solvent-borne consolidant is often required. Understanding the mode of penetration of consolidants into fossil bone is of crucial importance. It is governed by a variety of factors; neutron imaging is a powerful tool to monitor and visualise this penetration (non-destructively). The consolidation of a vertebrate fossil from the Maastrichtian of the southeast Netherlands was imaged at the High Flux Reactor facility at Petten, the Netherlands. The analysis shows current conservation practice to result in a sufficiently deep and isotropic penetration.


2019 ◽  
Vol 54 (9) ◽  
pp. 1217-1231 ◽  
Author(s):  
Ebrahim Oromiehie ◽  
Ulf Garbe ◽  
B Gangadhara Prusty

Automated fibre placement-based manufacturing technology is increasingly being used in several engineering applications. Manufacture of carbon fibre-reinforced plastic’s small/large structures have been made possible due to its remarkable capabilities like productivity and accuracy. Nevertheless, making high-quality composite laminate using automated fibre placement relies on the proper selection of critical processing variables to avoid internal flaws during the fibre placement process. Consequently, a reliable non-destructive inspection technique is required for quality assurance and structural integrity of fabricated laminates. Neutron radiography/tomography offers unique imaging capabilities over a wide range of applications including fibre-reinforced polymer composites. The application of this technique towards tomographic reconstruction of automated fibre placement-made thermoplastic composites is presented in this paper. It is shown that the porosity analysis using neutron imaging technique provides reliable information. Additionally, using such technique valuable data regarding the size and the location of the voids in the laminate can be acquired and informed. This will assist the composite structural analysts and designers to select the appropriate processing parameters towards a defect free automated fibre placement part manufacture.


2016 ◽  
Vol 56 (5) ◽  
pp. 388-394 ◽  
Author(s):  
Jan Šácha ◽  
Michal Sněhota ◽  
Jan Hovind

This paper presents an empirical method by Kang et al. recently proposed for correcting two-dimensional neutron radiography for water quantification in soil. The method was tested on data from neutron imaging of the water infiltration in a soil sample. The raw data were affected by neutron scattering and by beam hardening artefacts. Two strategies for identifying the correction parameters are proposed in this paper. The method has been further developed for the case of three-dimensional neutron tomography. In a related experiment, neutron imaging is used to record ponded-infiltration experiments in two artificial soil samples. Radiograms, i.e., two-dimensional projections of the sample, were acquired during infiltration. A calculation was made of the amount of water and its distribution within the radiograms, in the form of two-dimensional water thickness maps. Tomograms were reconstructed from the corrected and uncorrected water thickness maps to obtain the 3D spatial distribution of the water content within the sample. Without the correction, the beam hardening and the scattering effects overestimated the water content values close to the perimeter of the sample, and at the same time underestimated the values close to the centre of the sample. The total water content of the entire sample was the same in both cases. The empirical correction method presented in this study is a relatively accurate, rapid and simple way to obtain the quantitatively determined water content from two-dimensional and three-dimensional neutron images. However, an independent method for measuring the total water volume in the sample is needed in order to identify the correction parameters.


2000 ◽  
Vol 33 (5) ◽  
pp. 1253-1261 ◽  
Author(s):  
Y. T. Cheng ◽  
D. F. R. Mildner ◽  
H. H. Chen-Mayer ◽  
V. A. Sharov ◽  
C. J. Glinka

Small-angle neutron scattering (SANS) measurements have been performed on long-flight-path pinhole-collimation SANS instruments using, as a two-dimensional position-sensitive detector, both a neutron imaging plate, incorporating gadolinium, and a two-step transfer method, with dysprosium foil as the image transfer medium. The measurements are compared with corresponding data taken using conventional position-sensitive gas proportional counters on the SANS instruments in order to assess the viability of the imaging techniques. The imaging plates have pixel sizes of about two orders of magnitude smaller than those of the gas proportional counter. The reduced pixel size provides definite advantages over the gas counter in certain specific situations, namely when limited space necessitates a short sample-to-detector distance, when only small samples (comparable in size to the detector pixels) are available, or when used in conjunction with focusing beam optics.


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