Optimization of bent perfect Si(220)-crystal monochromator for residual strain/stress instrument—Part II

Moon, Myungkook; Em, V. T.; Lee, Changhee; Mikula, P.; Hong, Kwangpyo; Choi, Yong Eui; Cheon, Jong-Kyu; Nam, Uk-Won; Kong, Kyung-Nam; Jin, Kyung-Chan

doi:10.1016/j.physb.2005.06.044

Cited by 14 publications

(2 citation statements)

References 10 publications

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“…It has been reported that with the use of neutron wavelength λ = 2.39 Å near the Bragg edge (112) by Si(111) monochromator, the (110) diffraction plane of the ferritic steel can enhance the path length up to 83 mm with a gauge volume of 80 mm 3 in ferritic steels [9]. Furthermore, it should be mentioned that a bent perfect crystal is necessary for the silicon monochromator in order to increase the neutron beam intensity by focusing it, and it is accepted as an effective device for the stress diffractometer [14][15][16][17]. For the residual stress analysis, the stress tensor components are usually calculated based on the generalized Hooke's law [1].…”

Section: Introductionmentioning

confidence: 99%

Neutron Diffraction Measurements of Residual Stresses for Ferritic Steel Specimens over 80 mm Thick

Em,

Ivan,

Woo

et al. 2024

Metals

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The maximum thickness for ferritic steel specimens’ residual stress measurements using neutron diffraction is known to be about 80 mm. This paper proposes a new neutron diffraction configuration of residual stress measurements for cases that are over 80 mm thick. The configuration utilizes a neutron beam with a wavelength of 1.55 Å diffracted from the (220) plane with a diffraction angle (2θ) of 99.4°. The reason for the deep penetration capability is attributed to the chosen wavelength having enough intensities due to the low cross-section near the Bragg edge and the reduced beam path length (~16 mm) reflected by the large diffraction angle. Neutron diffraction experiments with this configuration can decrease strain errors up to ±150 με, corresponding to a stress of about ±30 MPa.

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Section: Introductionmentioning

confidence: 99%

Neutron Diffraction Measurements of Residual Stresses for Ferritic Steel Specimens over 80 mm Thick

Em,

Ivan,

Woo

et al. 2024

Metals

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“…It has been suggested that the path length can be maximized when the wavelength is located at the local minimum of the neutron total cross-section near but off the Bragg edges [4]. Moreover, the available path length in steels can be remarkably increased with the benefit of the focusing bent perfect crystal Si monochromators [5][6][7][8]. Here, we propose two instrumental configurations of the neutron diffraction to provide the maximized available penetration path length in reflection (D ref ) and transmission (D tr ) geometries for the low-textured ferritic steel (a-Fe, bcc structure) in Table 1.…”

Section: Introductionmentioning

confidence: 99%

Residual stress determination in a thick ferritic steel weld plate using neutron diffraction

Woo

Seong

et al. 2012

J Mater Sci

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The distribution of residual stresses was determined through the thickness of a 50-mm thick ferritic steel weld plate using (110) and/or (211) diffraction peaks. We proposed a two-peak combined methodology, which uses (110) and (211) peaks designed to have neutron wavelengths of 2.39 and 1.55 Å , respectively, in order to locate the neutron cross-section at each local minimum. The result shows that the available penetration path length can be maximized by (110) diffraction for the transmission geometry and (211) diffraction for the reflection geometry of the plate specimen. Furthermore, the stress components by the two peaks were similar to the results of the conventional one-peak measurement due to the same diffraction elastic constants between the (110) and (211) peaks in the bcc ferritic steel. Such appropriately combined twopeak method can significantly enhance the deep penetration capability for the determination of residual stresses in an extra thick steel plate specimen.

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Focusing Optics for Neutrons

Ott

Springer Series in Optical Science

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Optimization of bent perfect Si(220)-crystal monochromator for residual strain/stress instrument—Part II

Cited by 14 publications

References 10 publications

Neutron Diffraction Measurements of Residual Stresses for Ferritic Steel Specimens over 80 mm Thick

Neutron Diffraction Measurements of Residual Stresses for Ferritic Steel Specimens over 80 mm Thick

Residual stress determination in a thick ferritic steel weld plate using neutron diffraction

Focusing Optics for Neutrons

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