scholarly journals Depth capabilities of neutron and synchrotron diffraction strain measurement instruments. I. The maximum feasible path length

2004 ◽  
Vol 37 (4) ◽  
pp. 596-606 ◽  
Author(s):  
Philip John Withers
Keyword(s):  
Strain Measurement ◽  
Path Length ◽  
Measurement Accuracy ◽  
Companion Paper ◽  
Peak Height ◽  
Acquisition Time ◽  
Measurement Instruments ◽  
X Ray ◽  
Sampling Volume ◽  
Feasible Path

In this paper an algorithm is presented for estimating the maximum feasible penetration path length for neutron and synchrotron X-ray strain measurement instruments. This reflects the attenuation and scattering capability of the material under examination, the incident flux and detector arrangement, the likely background signal, the required strain measurement accuracy, the sampling volume and the diffracting geometry. Its validity and generality is examined through a consideration of data collected using a number of instruments on a variety of materials. Two criteria for the maximum feasible path length are examined: one based on the maximum acquisition time, the other based on the minimum acceptable peak height to background ratio. As demonstrated in the companion paper [part II: Withers (2004).J. Appl. Cryst.37, 607–612], the algorithm can be used to delineate those conditions under which neutron and synchrotron X-ray radiations can provide useful information and to identify which is most suited to any particular measurement task.

scholarly journals Depth capabilities of neutron and synchrotron diffraction strain measurement instruments. II. Practical implications

2004 ◽  
Vol 37 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Philip John Withers
Keyword(s):  
Strain Measurement ◽  
Measurement Accuracy ◽  
Radiation Energy ◽  
Calibration Data ◽  
Measurement Instruments ◽  
Penetration Length ◽  
Wide Range ◽  
Sampling Volume ◽  
Practical Implications ◽  
Transmission And Reflection

In part I [Withers (2004).J. Appl. Cryst.37, 596–606], a framework was presented for estimating the maximum feasible penetration length for neutron and synchrotron X-ray strain measurement. This calculation reflected the attenuation and scattering capability of the material under examination, the incident flux and detector arrangement, the likely background signal, the required strain measurement accuracy, the sampling volume, and the diffracting geometry. In the present paper (part II), preliminary calibration data acquired for a very wide range of neutron and synchrotron sources are presented. This database is used to explore the implications of the framework for delineating those conditions under which a specific instrument can provide useful information within a feasible timescale, in order to identify the most appropriate radiation, energy and instrumental configuration for undertaking measurements in transmission and reflection as a function of depth, and to establish guiding principles for improving the performance of existing instruments.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

Electronic Package Failure Analysis Using TDR

2000 ◽  
Author(s):  
Dima A. Smolyansky
Keyword(s):  
Failure Analysis ◽  
Fault Location ◽  
Measurement Accuracy ◽  
Time Domain Reflectometry ◽  
Acoustic Imaging ◽  
X Ray ◽  
Analysis Techniques ◽  
Bga Packages ◽  
Impedance Profile ◽  
Nature Of Time

Abstract The visual nature of Time Domain Reflectometry (TDR) makes it a very natural technology that can assist with fault location in BGA packages, which typically have complex interweaving layouts that make standard failure analysis techniques, such as acoustic imaging and X-ray, less effective and more difficult to utilize. This article discusses the use of TDR for package failure analysis work. It analyzes in detail the TDR impedance deconvolution algorithm as applicable to electronic packaging fault location work, focusing on the opportunities that impedance deconvolution and the resulting true impedance profile opens up for such work. The article examines the TDR measurement accuracy and the comparative package failure analysis, and presents three main considerations for package failure analysis. It also touches upon the goal and the task of the failure analysts and TDR's specific signatures for the open and short connections.

scholarly journals Simple low dose radiography allows precise lung volume assessment in mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amara Khan ◽  
Andrea Markus ◽  
Thomas Rittmann ◽  
Jonas Albers ◽  
Frauke Alves ◽  
...  
Keyword(s):  
Lung Function ◽  
Whole Body ◽  
Acquisition Time ◽  
Micro Ct ◽  
Lung Volumes ◽  
X Ray ◽  
Promising Tool ◽  
Volume Assessment ◽  
Set Up ◽  
Time Required

AbstractX-ray based lung function (XLF) as a planar method uses dramatically less X-ray dose than computed tomography (CT) but so far lacked the ability to relate its parameters to pulmonary air volume. The purpose of this study was to calibrate the functional constituents of XLF that are biomedically decipherable and directly comparable to that of micro-CT and whole-body plethysmography (WBP). Here, we developed a unique set-up for simultaneous assessment of lung function and volume using XLF, micro-CT and WBP on healthy mice. Our results reveal a strong correlation of lung volumes obtained from radiographic XLF and micro-CT and demonstrate that XLF is superior to WBP in sensitivity and precision to assess lung volumes. Importantly, XLF measurement uses only a fraction of the radiation dose and acquisition time required for CT. Therefore, the redefined XLF approach is a promising tool for preclinical longitudinal studies with a substantial potential of clinical translation.

Full-field X-ray diffraction microscopy using polymeric compound refractive lenses

2014 ◽  
Vol 47 (6) ◽  
pp. 1882-1888 ◽  
Author(s):  
J. Hilhorst ◽  
F. Marschall ◽  
T. N. Tran Thi ◽  
A. Last ◽  
T. U. Schülli
Keyword(s):  
Imaging Techniques ◽  
Light And Electron Microscopy ◽  
Added Value ◽  
Acquisition Time ◽  
Imaging Method ◽  
X Ray Diffraction ◽  
Polymeric Compound ◽  
Full Field ◽  
X Ray ◽  
Diffraction Imaging

Diffraction imaging is the science of imaging samples under diffraction conditions. Diffraction imaging techniques are well established in visible light and electron microscopy, and have also been widely employed in X-ray science in the form of X-ray topography. Over the past two decades, interest in X-ray diffraction imaging has taken flight and resulted in a wide variety of methods. This article discusses a new full-field imaging method, which uses polymer compound refractive lenses as a microscope objective to capture a diffracted X-ray beam coming from a large illuminated area on a sample. This produces an image of the diffracting parts of the sample on a camera. It is shown that this technique has added value in the field, owing to its high imaging speed, while being competitive in resolution and level of detail of obtained information. Using a model sample, it is shown that lattice tilts and strain in single crystals can be resolved simultaneously down to 10−3° and Δa/a= 10−5, respectively, with submicrometre resolution over an area of 100 × 100 µm and a total image acquisition time of less than 60 s.

Strain Measurement by X-ray Diffraction Methods

1949 ◽  
Vol 1 (3) ◽  
pp. 211-224
Author(s):  
G. B. Greenough
Keyword(s):  
Strain Measurement ◽  
Plastic Anisotropy ◽  
Stress And Strain ◽  
Routine Method ◽  
X Ray Diffraction ◽  
Strain Measurements ◽  
X Ray ◽  
The Past ◽  
Polycrystalline Metals ◽  
The Individual

SummaryMany papers have been written on the measurement of strain by X-ray diffraction methods and on the interpretation of these strains in terms of stresses. Whereas, during the past few years, the experimental methods of determining the strains have. remained largely unchanged, research has shown that the older techniques for calculating stresses from strains are not always valid.In this paper an attempt is made to describe some of the principles of strain measurement by X-ray diffraction methods to those who are unfamiliar with the methods. The types of stress and strain systems which may exist in polycrystalline metals are then considered, particular attention being paid to the effect of the elastic and plastic anisotropy of the individual crystals. Some indication is given as to how the earlier methods of interpreting X-ray strain measurements should be modified, but no rigid routine method is proposed for use in a general case.

Abstract 2806: Whole Heart Coronary Magnetic Resonance Angiography Using 32-Channel Cardiac Coils and High Parallel Imaging Factor

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Motonori Nagata ◽  
Hajime Sakuma ◽  
Nanaka Ishida ◽  
Hiroshi Nakajima ◽  
Masaki Ishida ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Angiography ◽  
Parallel Imaging ◽  
Noninvasive Detection ◽  
Acquisition Time ◽  
Luminal Diameter ◽  
X Ray ◽  
Coronary Mra ◽  
Imaging Time ◽  
Whole Heart

PURPOSE Coronary MRA provides noninvasive detection of coronary artery disease (CAD) without administration of contrast medium or exposing the patient to radiation. However, use of coronary MRA in excluding patients with CAD has been limited due to lengthy imaging time. The purpose of this study was to reduce acquisition time of coronary MRA by using 32 channel cardiac coils and high parallel imaging factor, and to evaluate diagnostic performance of this method in detecting significant CAD. METHOD AND MATERIALS Sixty-two patients with suspected CAD were studied. Free-breathing coronary MRA encompassing the entire heart was acquired by using 32-channel coils and SENSE factor of 4. After monitoring motion of the coronary artery on cine MRI, MR angiograms were acquired during diastole in 46 patients (acquisition window 82±57ms) and during systole in 16 patients (50±19ms). Coronary MRA images were interpreted by 2 observers by employing a sliding SLAB MIP method. All patients underwent X-ray coronary angiography within 4 weeks from MRA, and significant CAD was defined as a luminal diameter reduction of 50% or more by QCA. All lesions with a reference diameter of 2mm or more on X-ray angiography were included when determining the accuracy of coronary MRA. RESULTS Acquisition of MRA was completed in all 62 patients, with the averaged imaging time of 6.1±2.6min. High SENSE factor achieved by 32-channel coils resulted in substantial reduction of imaging time by factor of >2, with the image quality score (4.6±0.2) at least equivalent to that by conventional 5-channel coils and SENSE factor of 2 (4.5±0.2). Significant CAD was observed on X-ray coronary angiography in 39 patients. MRA detected 33(85%) of 39 patients having CAD, with high specificity of 96%(22/23). All 16 patients with double- or triple-vessel diseases were detected by MRA. On a vessel based analysis, Whole-heart coronary MRA demonstrated sensitivity of 83%(49/59), specificity of 94%(119/127) and NPV of 92%(119/129). CONCLUSION Whole-heart coronary MRA with 1.5T MR imager and 32-chennel coils permits noninvasive detection of CAD with substantially reduced imaging time and high study success rate. High NPV (>90%) indicated the value of this approach in ruling out significant CAD.

Reducing Supervision of Quantitative Image Analysis of Meteorite Samples

2019 ◽  
Vol 26 (1) ◽  
pp. 63-75
Author(s):  
Ellen J. Crapster-Pregont ◽  
Denton S. Ebel
Keyword(s):  
Acquisition Time ◽  
Post Processing ◽  
Geological Samples ◽  
X Ray ◽  
Electron Probe Micro Analyzer ◽  
Time Restrictions ◽  
Number Of Factors ◽  
Quantitative Image ◽  
Potential Applications ◽  
Intensity Map

AbstractWhen selecting a method for determining modal mineralogy and elemental composition of geological samples (e.g., meteorites), a number of factors should be considered, includingthe number of objects or the area to be analyzed; the scale of expected chemical variation; instrument time restrictions; and post-processing time. This study presents a method that minimizes acquisition time while maintaining the ability to distinguish minerals based on combinations of intensities of electron probe micro-analyzer-generated X-ray element maps. While some other methods yield similar outcomes, this method's post-processing utilizes standard parameterized, X-ray intensity “map math” in an algorithm that is adaptable and requires minimal supervision once implemented. This study's minimized supervision in the post-processing of X-ray intensity maps decreases analysis time and its adaptability increases the number of potential applications. The method also facilitates calibration of the exact locations of analysis using laser ablation methods. While the method described here has advantages, the choice of method always depends on the question being asked.

Evaluation of Corrections for X-Ray Microanalysis in the ESEM

2001 ◽  
Vol 7 (S2) ◽  
pp. 698-699
Author(s):  
Robert A. Carlton ◽  
Charles E. Lyman ◽  
James E. Roberts ◽  
Raynald Gauvin
Keyword(s):  
Electron Beam ◽  
Vapor Pressure ◽  
Path Length ◽  
High Vacuum ◽  
Chamber Pressure ◽  
Environmental Scanning ◽  
X Ray ◽  
Scattering Effects ◽  
Beam Scattering ◽  
The Relationship

A number of methods have been proposed to correct for the electron beam scattering effects on xray microanalysis in the environmental scanning electron microscope (ESEM). This paper presents an evaluation of two of these methods. The Doehne method is based on the observation that x-ray counts due to the unscattered electron beam increase with decreasing chamber pressure whereas the inverse is true for x-ray counts due to scattered electrons. The x-ray count intercept, at zero pressure, of the regression lines relating x-ray counts to chamber vapor pressure is an estimate of the high-vacuum intensity. The Gauvin method is based on the relationship between x-ray counts and the fraction of the electron beam that is unscattered, fp.The fraction of the unscattered beam is calculated using an equation derived from scattering theory and uses the accelerating voltage, the gas path length, and the chamber vapor pressure.

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