Time-resolved X-ray PIV technique for diagnosing opaque biofluid flow with insufficient X-ray fluxes

2013 ◽  
Vol 20 (3) ◽  
pp. 498-503 ◽  
Author(s):  
Sung Yong Jung ◽  
Han Wook Park ◽  
Bo Heum Kim ◽  
Sang Joon Lee
Keyword(s):  
Temporal Resolution ◽  
Exposure Time ◽  
High Speed ◽  
Light Flux ◽  
Image Intensifier ◽  
Time Resolved ◽  
X Ray ◽  
Physiological Conditions ◽  
Blood Flows ◽  
X Ray Imaging

X-ray imaging is used to visualize the biofluid flow phenomena in a nondestructive manner. A technique currently used for quantitative visualization is X-ray particle image velocimetry (PIV). Although this technique provides a high spatial resolution (less than 10 µm), significant hemodynamic parameters are difficult to obtain under actual physiological conditions because of the limited temporal resolution of the technique, which in turn is due to the relatively long exposure time (∼10 ms) involved in X-ray imaging. This study combines an image intensifier with a high-speed camera to reduce exposure time, thereby improving temporal resolution. The image intensifier amplifies light flux by emitting secondary electrons in the micro-channel plate. The increased incident light flux greatly reduces the exposure time (below 200 µs). The proposed X-ray PIV system was applied to high-speed blood flows in a tube, and the velocity field information was successfully obtained. The time-resolved X-ray PIV system can be employed to investigate blood flows at beamlines with insufficient X-ray fluxes under specific physiological conditions. This method facilitates understanding of the basic hemodynamic characteristics and pathological mechanism of cardiovascular diseases.

scholarly journals Thermal behavior of single-crystal scintillators for high-speed X-ray imaging

2019 ◽  
Vol 26 (1) ◽  
pp. 205-214 ◽  
Author(s):  
Alan Kastengren
Keyword(s):  
Single Crystal ◽  
High Speed ◽  
Thermal Loading ◽  
Indirect Detection ◽  
X Rays ◽  
Time Resolved ◽  
X Ray ◽  
Damage And Failure ◽  
Light Levels ◽  
X Ray Imaging

Indirect detection of X-rays using single-crystal scintillators is a common approach for high-resolution X-ray imaging. With the high X-ray flux available from synchrotron sources and recent advances in high-speed visible-light cameras, these measurements are increasingly used to obtain time-resolved images of dynamic phenomena. The X-ray flux on the scintillator must, in many cases, be limited to avoid thermal damage and failure of the scintillator, which in turn limits the obtainable light levels from the scintillator. In this study, a transient one-dimensional numerical simulation of the temperature and stresses within three common scintillator crystals (YAG, LuAG and LSO) used for high-speed X-ray imaging is presented. Various conditions of thermal loading and convective cooling are also presented.

scholarly journals X-Ray Imaging Calibration for Fuel-Coolant Interaction Experimental Facilities

2021 ◽  
Vol 253 ◽  
pp. 06005
Author(s):  
Christophe Journeau ◽  
Michael Johnson ◽  
Shifali Singh ◽  
Fréderic Payot ◽  
Ken-ichi Matsuba ◽  
...  
Keyword(s):  
Test Section ◽  
High Speed ◽  
Limit Of Detection ◽  
Image Intensifier ◽  
Precise Determination ◽  
Severe Accident ◽  
X Ray ◽  
X Ray Imaging ◽  
Experimental Facilities ◽  
Lower Limits

During a severe accident in either sodium-cooled or water-cooled nuclear reactors, jets of molten nuclear fuel may impinge on the coolant resulting in fuel-coolant interactions (FCI). Experimental programs are being conducted to study this phenomenology and to support the development of severe accident models. Due to the optical opacity of the test section walls, sodium coolant, and the apparent optical opacity of water in the presence of intense ebullition, high-speed X-ray imaging is the preferred technique for FCI visualization. The configuration of these X-ray imaging systems, whereby the test section is installed between a fan-beam X-ray source and a scintillator-image intensifier projecting an image in the visual spectrum onto a high-speed camera, entails certain imaging artefacts and uncertainties. The X-ray imaging configuration requires precise calibration to enable detailed quantitative characterization of the FCI. To this end, ‘phantom’ models have been fabricated using polyethylene, either steel or hafnia powder, and empty cavities to represent sodium, molten fuel and sodium vapor phases respectively. A checkerboard configuration of the phantom enables calibration and correction for lens distortion artefacts which magnify features towards the edge of the field of view. Polydisperse steel ball configurations enable precise determination of the lower limit of detection and the estimation of parallax errors which introduce uncertainty in an object’s silhouette dimensions. Calibration experiments at the MELT facility determined lower limits of detection in the order of 4 mm for steel spheres, and 1.7-3.75 mm for vapor films around a molten jet.

High-speed X-ray imaging camera for time-resolved diffraction studies

2002 ◽  
Vol 49 (5) ◽  
pp. 2415-2419 ◽  
Author(s):  
S.V. Tipnis ◽  
V.V. Nagarkar ◽  
V. Gaysinskiy ◽  
S.R. Muller ◽  
I. Shestakova
Keyword(s):  
High Speed ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Imaging ◽  
Imaging Camera

Usage of CO2microbubbles as flow-tracing contrast media in X-ray dynamic imaging of blood flows

2014 ◽  
Vol 21 (5) ◽  
pp. 1160-1166 ◽  
Author(s):  
Sang Joon Lee ◽  
Han Wook Park ◽  
Sung Yong Jung
Keyword(s):  
Blood Flow ◽  
Contrast Media ◽  
Operation Time ◽  
Velocity Fields ◽  
Dynamic Imaging ◽  
Operating Conditions ◽  
Time Resolved ◽  
X Ray ◽  
Blood Flows ◽  
X Ray Imaging

X-ray imaging techniques have been employed to visualize various biofluid flow phenomena in a non-destructive manner. X-ray particle image velocimetry (PIV) was developed to measure velocity fields of blood flows to obtain hemodynamic information. A time-resolved X-ray PIV technique that is capable of measuring the velocity fields of blood flows under real physiological conditions was recently developed. However, technical limitations still remained in the measurement of blood flows with high image contrast and sufficient biocapability. In this study, CO2microbubbles as flow-tracing contrast media for X-ray PIV measurements of biofluid flows was developed. Human serum albumin and CO2gas were mechanically agitated to fabricate CO2microbubbles. The optimal fabricating conditions of CO2microbubbles were found by comparing the size and amount of microbubbles fabricated under various operating conditions. The average size and quantity of CO2microbubbles were measured by using a synchrotron X-ray imaging technique with a high spatial resolution. The quantity and size of the fabricated microbubbles decrease with increasing speed and operation time of the mechanical agitation. The feasibility of CO2microbubbles as a flow-tracing contrast media was checked for a 40% hematocrit blood flow. Particle images of the blood flow were consecutively captured by the time-resolved X-ray PIV system to obtain velocity field information of the flow. The experimental results were compared with a theoretically amassed velocity profile. Results show that the CO2microbubbles can be used as effective flow-tracing contrast media in X-ray PIV experiments.

scholarly journals High-speed x-ray imaging with the Keck pixel array detector (Keck PAD) for time-resolved experiments at synchrotron sources

2016 ◽  
Author(s):  
Hugh T. Philipp ◽  
Mark W. Tate ◽  
Prafull Purohit ◽  
Darol Chamberlain ◽  
Katherine S. Shanks ◽  
...  
Keyword(s):  
High Speed ◽  
Array Detector ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Imaging ◽  
Pixel Array ◽  
Pixel Array Detector

scholarly journals Influence of the laser cutting front geometry on the striation formation analysed with high-speed synchrotron X-ray imaging

2021 ◽  
Vol 1135 (1) ◽  
pp. 012009
Author(s):  
Jannik Lind ◽  
Christian Hagenlocher ◽  
David Blazquez-Sanchez ◽  
Marc Hummel ◽  
A. Olowinsky ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Laser Beam ◽  
Film Thickness ◽  
High Speed ◽  
Angle Of Incidence ◽  
Time Resolved ◽  
X Ray ◽  
Cut Edge ◽  
Local Increase ◽  
X Ray Imaging

Abstract The generation of low surface roughness of the cut edge during laser beam cutting is a challenge. The striation pattern, which determines the surface roughness, can be distinguished into regular and interrupted striations, the latter resulting in an increased surface roughness. In order to analyse their formation, the space- and time-resolved cutting front geometry and melt film thickness were captured during laser beam fusion cutting of aluminium sheets with a framerate of 1000 Hz by means of high-speed synchrotron X-ray imaging. The comparison of the contours of the cutting fronts for a cut result with regular und interrupted striations shows that the contour fluctuates significantly more in case of interrupted striations. This leads to a strong fluctuation of the local angle of incidence. In addition, the average angle of incidence decreases, which results in an increase of the average absorbed irradiance. Both phenomena, local increase of absorbed irradiance and its dynamic fluctuation, result in a local increase of the melt film thickness at the cutting front which is responsible for the formation of the interrupted striations.

UFO — a scalable platform for high-speed synchrotron X-ray imaging

2016 ◽  
Author(s):  
Andreas Kopmann ◽  
Suren Chilingaryan ◽  
Matthias Vogelgesang ◽  
Timo Dritschler ◽  
Andrey Shkarin ◽  
...  
Keyword(s):  
High Speed ◽  
X Ray ◽  
X Ray Imaging

syris: a flexible and efficient framework for X-ray imaging experiments simulation

2017 ◽  
Vol 24 (6) ◽  
pp. 1283-1295 ◽  
Author(s):  
Tomáš Faragó ◽  
Petr Mikulík ◽  
Alexey Ershov ◽  
Matthias Vogelgesang ◽  
Daniel Hänschke ◽  
...  
Keyword(s):  
Motion Estimation ◽  
Data Processing ◽  
Graphics Processing Units ◽  
High Speed ◽  
Real Data ◽  
Estimation Accuracy ◽  
Processing Parameter ◽  
X Ray ◽  
X Ray Imaging ◽  
Imaging Conditions

An open-source framework for conducting a broad range of virtual X-ray imaging experiments,syris, is presented. The simulated wavefield created by a source propagates through an arbitrary number of objects until it reaches a detector. The objects in the light path and the source are time-dependent, which enables simulations of dynamic experiments,e.g.four-dimensional time-resolved tomography and laminography. The high-level interface ofsyrisis written in Python and its modularity makes the framework very flexible. The computationally demanding parts behind this interface are implemented in OpenCL, which enables fast calculations on modern graphics processing units. The combination of flexibility and speed opens new possibilities for studying novel imaging methods and systematic search of optimal combinations of measurement conditions and data processing parameters. This can help to increase the success rates and efficiency of valuable synchrotron beam time. To demonstrate the capabilities of the framework, various experiments have been simulated and compared with real data. To show the use case of measurement and data processing parameter optimization based on simulation, a virtual counterpart of a high-speed radiography experiment was created and the simulated data were used to select a suitable motion estimation algorithm; one of its parameters was optimized in order to achieve the best motion estimation accuracy when applied on the real data.syriswas also used to simulate tomographic data sets under various imaging conditions which impact the tomographic reconstruction accuracy, and it is shown how the accuracy may guide the selection of imaging conditions for particular use cases.

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