X-Ray Characterization of Defects in Irradiated Iron

1990 ◽  
Vol 209 ◽  
Author(s):  
J. Peisl ◽  
H. Franz ◽  
A. Schmalzbauer ◽  
G. Wallner
Keyword(s):  
Thermal Annealing ◽  
Lattice Parameter ◽  
X Rays ◽  
Spatial Correlations ◽  
X Ray ◽  
Single Defect ◽  
Angle Scattering ◽  
Correlation Volume ◽  
Induced Defects ◽  
Irradiation Induced Defects

ABSTRACTWe report on a thorough X-ray study of irradiation induced defects in iron. Single crystals were irradiated at 4.6 K with reactor neutrons and at 90 K with 2 MeV electrons. After irradiation and subsequent thermal annealing, we measured the defect induced diffuse scattering of X-rays (Huang scattering) and the small angle scattering of synchrotron radiation. Simultaneously, lattice parameter and electrical resistivity changes were measured. The single defect properties are determined from low dose electron irradiated samples and yield the lattice distortions, i.e., the volume change and defect symmetry as described by the force dipole tensor. Excellent agreement of the experimental results with calculated values from literature is observed. After neutron irradiation, defects are correlated within displacement cascades. The correlations for vacanciesand interstitials are described by a spatial correlation volume. These results are compared with computer simulations usingthe Marlowe code. During thermal annealing the irradiation induced defects agglomerate at characteristic temperatures and we observe changes in the spatial correlations of the defects. There is a clear difference between electron and neutron irradiated samples concerning defect recovery in stage 1.

Mesoscopic structure of SiC fibers by neutron and x-ray scattering

1996 ◽  
Vol 11 (5) ◽  
pp. 1169-1178 ◽  
Author(s):  
Kentaro Suzuya ◽  
Michihiro Furusaka ◽  
Noboru Watanabe ◽  
Makoto Osawa ◽  
Kiyohito Okamura ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Volume Fraction ◽  
X Rays ◽  
X Ray ◽  
Sic Fibers ◽  
X Ray Scattering ◽  
Mesoscopic Structure ◽  
Angle Scattering ◽  
Momentum Transfer Range ◽  
First Time

Mesoscopic structures of SiC fibers produced from polycarbosilane by different methods were studied by diffraction and small-angle scattering of neutrons and x-rays. Microvoids of a size of 4–10 Å in diameter have been observed for the first time by neutron scattering in a medium momentum transfer range (Q = 0.1–1.0 Å−1). The size and the volume fraction of β–SiC particles were determined for fibers prepared at different heat-treatment temperatures. The results show that wide-angle neutron scattering measurements are especially useful for the study of the mesoscopic structure of multicomponent materials.

The Atomic Order in Guinier-Preston Zones of Aluminum-Silver Alloys

1963 ◽  
Vol 7 ◽  
pp. 1-13 ◽  
Author(s):  
Volkmar Gerold ◽  
Heinz Auer ◽  
Winfried Merz
Keyword(s):  
Room Temperature ◽  
Three Dimensional ◽  
Miscibility Gap ◽  
X Rays ◽  
Atomic Order ◽  
Zone Size ◽  
X Ray ◽  
Angle Scattering ◽  
Diffraction Patterns ◽  
Step Quenching

AbstractThe formation of the spherical Guinier—Preston zones in an aluminum-silver alloy is governed by a metastable miscibility gap, which consists of two different sections. The lower section occurs below 170°C (η state), the higher section up to 420°C (∊ state). The zones in the two sections differ in their silver concentration and in their atomic order. To prove the change in order, a combination of X-ray small-angle scattering and electric resistivity measurements was used. As the resistivity depends on the zone size and the atomic order, the change in order can be found when the zone size is known. This size was measured by the X-ray technique. To complete the results, X-rays ingle-crystal diffraction patterns with monochromatic radiation were taken at different stages. According to these patterns, three different states must be distinguished.The η′ state exists at room temperature after quenching from 550°C. The silver atoms prefer a layered arrangement in the zones, which is not very stable. It is destroyed after short annealings above 100°C. The η state is developed during annealing below 170°C. A three-dimensional atomic order is built up with increasing zone size, which results in a marked decrease in the resistivity. For the ∊ state (above 170°C), a nearly random atomic distribution exists. Step-quenching experiments prove that the ordered η state can also be developed at room temperature.

Thermal annealing of X-ray-induced defects in Sr-doped KCl crystals

1972 ◽  
Vol 12 (1) ◽  
pp. 307-315 ◽  
Author(s):  
I. Katz ◽  
B. Chenfoux ◽  
N. Kristianpoller
Keyword(s):  
Thermal Annealing ◽  
X Ray ◽  
Induced Defects

Small-angle scattering of X-rays in a conventional Bragg–Brentano diffractometer for quantitative analysis

1995 ◽  
Vol 10 (3) ◽  
pp. 170-172
Author(s):  
Stefano Battaglia
Keyword(s):  
Quantitative Analysis ◽  
Diffraction Analysis ◽  
Small Angle ◽  
Carbonate Rocks ◽  
International Standards ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Orientation Effects ◽  
Angle Scattering

A technique is presented utilizing an unmodified commercial X-ray diffractometer, equipped with a Bragg–Brentano geometry, for reducing preferred orientation effects in measured intensities during quantitative diffraction analysis. The diffractometer setup examined makes possible data acquisition with Θ fixed at 1° and 2Θ scanning the Bragg line. The results obtained with this technique are shown in the quantitative X-ray diffraction analysis of three international standards of carbonate rocks (401,402,403).

scholarly journals DLSR: a solution to the parallax artefact in X-ray diffraction computed tomography data

2020 ◽  
Vol 53 (6) ◽  
pp. 1531-1541
Author(s):  
A. Vamvakeros ◽  
A. A. Coelho ◽  
D. Matras ◽  
H. Dong ◽  
Y. Odarchenko ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Tomographic Reconstruction ◽  
Scale Up ◽  
Lattice Parameter ◽  
Chemical Information ◽  
X Rays ◽  
X Ray Diffraction ◽  
Major Barrier ◽  
X Ray ◽  
Tomography Data

A new tomographic reconstruction algorithm is presented, termed direct least-squares reconstruction (DLSR), which solves the well known parallax problem in X-ray-scattering-based experiments. The parallax artefact arises from relatively large samples where X-rays, scattered from a scattering angle 2θ, arrive at multiple detector elements. This phenomenon leads to loss of physico-chemical information associated with diffraction peak shape and position (i.e. altering the calculated crystallite size and lattice parameter values, respectively) and is currently the major barrier to investigating samples and devices at the centimetre level (scale-up problem). The accuracy of the DLSR algorithm has been tested against simulated and experimental X-ray diffraction computed tomography data using the TOPAS software.

Thermal Annealing of X-Ray-Induced Defects in Sr-Doped KCl Crystals

1972 ◽  
pp. 307-316
Author(s):  
I. Katz ◽  
B. Chenfoux ◽  
N. Kristianpoller
Keyword(s):  
Thermal Annealing ◽  
X Ray ◽  
Induced Defects

Small-angle energy-dispersive X-ray scattering using a laboratory-based diffractometer with a conventional source

2007 ◽  
Vol 40 (2) ◽  
pp. 218-231 ◽  
Author(s):  
Giuseppe Portale ◽  
Alessandro Longo ◽  
Lucio D'Ilario ◽  
Andrea Martinelli ◽  
Ruggero Caminiti ◽  
...  
Keyword(s):  
Small Angle ◽  
Energy Dispersive ◽  
Protein Solutions ◽  
X Rays ◽  
Catalytic Systems ◽  
X Ray ◽  
X Ray Scattering ◽  
Angle Scattering ◽  
Ray Patterns ◽  
Ray Scattering

The use of polychromaticBremsstrahlungX-rays generated by commercial tubes for energy-dispersive small-angle scattering measurements has not been extensively discussed in the literature, mainly because of some difficulties associated with it. If a suitable experimental setup is chosen and concomitant phenomena are taken into account for correcting the observed X-ray patterns, energy-dispersive small-angle X-ray scattering (SAXS) may become an interesting alternative to conventional measurements based on monochromatic beams. Energy-dispersive SAXS experiments carried out on protein solutions, micelles, semicrystalline polymers and catalytic systems are discussed to illustrate the new opportunities offered by this technique as well as its limitations.

Analysis of recovery process of low-dose neutron irradiation-induced defects in silicon nitride-based ceramics by thermal annealing

2014 ◽  
Vol 455 (1-3) ◽  
pp. 464-469 ◽  
Author(s):  
Areerak Rueanngoen ◽  
Koumei Kanazawa ◽  
Masamitsu Imai ◽  
Katsumi Yoshida ◽  
Toyohiko Yano
Keyword(s):  
Silicon Nitride ◽  
Thermal Annealing ◽  
Neutron Irradiation ◽  
Low Dose ◽  
Recovery Process ◽  
Induced Defects ◽  
Irradiation Induced Defects

scholarly journals Interface Evolution in a W/Si Multilayer after Rapid Thermal Annealing Studied by X-ray Reflectivity and Diffuse Scattering

1997 ◽  
Vol 30 (5) ◽  
pp. 642-646 ◽  
Author(s):  
M. Jergel ◽  
V. Holý ◽  
E. Majková ◽  
S. Luby ◽  
R. Senderák
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Diffuse Scattering ◽  
Grazing Incidence ◽  
Interface Roughness ◽  
X Rays ◽  
Interface Evolution ◽  
X Ray ◽  
Scattering Measurements ◽  
Highly Correlated

An interface study of the effect of rapid thermal annealing (RTA) in the temperature range 523–1273 K for 5–40 s on a nominally [(50 Å Si/10 Å W) × 9] amorphous multilayer (ML) deposited on an Si(100) wafer was performed by X-ray reflectivity and diffuse-scattering measurements at grazing incidence. The results of the X-ray reflectivity and diffuse-scattering measurements were evaluated by Fresnel optical computational code and within the distorted-wave Born approximation, respectively. Up to the 773 K/5 s annealing step, the r.m.s. interface roughness decreases by 30%, which brings about a reflectivity increase of 20% on the first Bragg maximum. There is a small overall increase of the r.m.s. interface roughness across the ML in the as-deposited state and the interface profiles are highly correlated. From the very beginning of RTA, the fractal interface behaviour is gradually lost and the lateral correlation length increases, this process being accompanied by a decrease of the interface conformality. This tendency continues during the 773 K/20 s annealing; however, the r.m.s. roughness evolution is reversed. During the 1023 K/5 s annealing, the interfaces are no longer `seen' by the X-rays and, during the 1273 K/5 s annealing, a total collapse of the ML structure takes place.

Annealing Effect of Thermal Conductivity on Thermal Stress Induced Fracture of Nuclear Graphite

2005 ◽  
Vol 297-300 ◽  
pp. 1698-1703
Author(s):  
Junya Sumita ◽  
Taiju Shibata ◽  
Masahiro Ishihara ◽  
Tatsuo Iyoku ◽  
Nobumasa Tsuji
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stress ◽  
Thermal Annealing ◽  
Fem Analysis ◽  
Fracture Probability ◽  
Annealing Effect ◽  
The Core ◽  
Nuclear Graphite ◽  
Induced Defects ◽  
Irradiation Induced Defects

Graphite materials are used for structural components in the core of high temperature gas-cooled reactors (HTGRs) because of their excellent thermo/mechanical properties. When the core temperature is raised at an accident, the thermal stress of the components is induced, and it enhances the fracture probability of them. In general, the thermal conductivity of graphite is decreased by neutron irradiation due to irradiation-induced defects preventing heat conduction by phonon. It is hence expected that decreased thermal conductivity is recovered to some extent by thermal annealing at the accident. Therefore, the consideration of the thermal annealing effect is placed as much important subject in the fracture/strength evaluation of the graphite components at the accident. In the present study, the thermal stress and the fracture probability of graphite components influenced by the thermal annealing were investigated by a finite element method (FEM) analysis. It was shown that the annealing effect decreases the thermal stress and a certain level of the fracture probability.

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