scholarly journals Translative lens-based full-field coherent X-ray imaging

2020 ◽  
Vol 27 (1) ◽  
pp. 119-126
Author(s):  
Carsten Detlefs ◽  
Mario Alejandro Beltran ◽  
Jean-Pierre Guigay ◽  
Hugh Simons
Keyword(s):  
Numerical Aperture ◽  
Objective Lens ◽  
X Rays ◽  
Resolution Limit ◽  
Radiation Dose Rate ◽  
Full Field ◽  
X Ray ◽  
X Ray Imaging ◽  
Imaging Approach ◽  
Potential Benefits

A full-field coherent imaging approach suitable for hard X-rays based on a classical (i.e. Galilean) X-ray microscope is described. The method combines a series of low-resolution images acquired at different transverse lens positions into a single high-resolution image, overcoming the spatial resolution limit set by the numerical aperture of the objective lens. The optical principles of the approach are described, the successful reconstruction of simulated phantom data is demonstrated, and aspects of the reconstruction are discussed. The authors believe that this approach offers some potential benefits over conventional scanning X-ray ptychography in terms of spatial bandwidth and radiation dose rate.

scholarly journals Highly porous nanoberyllium for X-ray beam speckle suppression

2015 ◽  
Vol 22 (3) ◽  
pp. 796-800 ◽  
Author(s):  
Alexander Goikhman ◽  
Ivan Lyatun ◽  
Petr Ershov ◽  
Irina Snigireva ◽  
Pawel Wojda ◽  
...  
Keyword(s):  
Spatial Coherence ◽  
Special Device ◽  
X Rays ◽  
Speckle Structure ◽  
Full Field ◽  
X Ray ◽  
X Ray Imaging ◽  
Phase Amplitude ◽  
Highly Porous ◽  
Effective Source

This paper reports a special device called a `speckle suppressor', which contains a highly porous nanoberyllium plate squeezed between two beryllium windows. The insertion of the speckle suppressor in an X-ray beam allows manipulation of the spatial coherence length, thus changing the effective source size and removing the undesirable speckle structure in X-ray imaging experiments almost without beam attenuation. The absorption of the nanoberyllium plate is below 1% for 1 mm thickness at 12 keV. The speckle suppressor was tested on the ID06 ESRF beamline with X-rays in the energy range from 9 to 15 keV. It was applied for the transformation of the phase–amplitude contrast to the pure amplitude contrast in full-field microscopy.

scholarly journals Progress in HAXPES performance combining full-field k-imaging with time-of-flight recording

2019 ◽  
Vol 26 (6) ◽  
pp. 1996-2012 ◽  
Author(s):  
K. Medjanik ◽  
S. V. Babenkov ◽  
S. Chernov ◽  
D. Vasilyev ◽  
B. Schönhense ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Time Of Flight ◽  
High Energy ◽  
Objective Lens ◽  
X Rays ◽  
Full Field ◽  
X Ray ◽  
Alternative Approach ◽  
Field Imaging ◽  
Phase Differences

An alternative approach to hard-X-ray photoelectron spectroscopy (HAXPES) has been established. The instrumental key feature is an increase of the dimensionality of the recording scheme from 2D to 3D. A high-energy momentum microscope detects electrons with initial kinetic energies up to 8 keV with a k-resolution of 0.025 Å−1, equivalent to an angular resolution of 0.034°. A special objective lens with k-space acceptance up to 25 Å−1 allows for simultaneous full-field imaging of many Brillouin zones. Combined with time-of-flight (ToF) parallel energy recording this yields maximum parallelization. Thanks to the high brilliance (1013 hν s−1 in a spot of <20 µm diameter) of beamline P22 at PETRA III (Hamburg, Germany), the microscope set a benchmark in HAXPES recording speed, i.e. several million counts per second for core-level signals and one million for d-bands of transition metals. The concept of tomographic k-space mapping established using soft X-rays works equally well in the hard X-ray range. Sharp valence band k-patterns of Re, collected at an excitation energy of 6 keV, correspond to direct transitions to the 28th repeated Brillouin zone. Measured total energy resolutions (photon bandwidth plus ToF-resolution) are 62 meV and 180 meV FWHM at 5.977 keV for monochromator crystals Si(333) and Si(311) and 450 meV at 4.0 keV for Si(111). Hard X-ray photoelectron diffraction (hXPD) patterns with rich fine structure are recorded within minutes. The short photoelectron wavelength (10% of the interatomic distance) `amplifies' phase differences, making full-field hXPD a sensitive structural tool.

scholarly journals Multiscale X-ray imaging using ptychography

2018 ◽  
Vol 25 (4) ◽  
pp. 1214-1221 ◽  
Author(s):  
Simone Sala ◽  
Venkata S. C. Kuppili ◽  
Stefanos Chalkidis ◽  
Darren J. Batey ◽  
Xiaowen Shi ◽  
...  
Keyword(s):  
Generation X ◽  
Imaging Techniques ◽  
X Rays ◽  
Widespread Application ◽  
Full Field ◽  
X Ray ◽  
X Ray Imaging ◽  
Imaging Mode ◽  
Resolution Imaging ◽  
Complementary Techniques

The success of ptychography and other imaging experiments at third-generation X-ray sources is apparent from their increasingly widespread application and the improving quality of the images they produce both for resolution and contrast and in terms of relaxation of experimental constraints. The wider availability of highly coherent X-rays stimulates the development of several complementary techniques which have seen limited mutual integration in recent years. This paper presents a framework in which some of the established imaging techniques – with particular regard for ptychography – are flexibly applied to tackle the variable requirements occurring at typical synchrotron experiments. In such a framework one can obtain low-resolution images of whole samples and smoothly zoom in on specific regions of interest as they are revealed by switching to a higher-resolution imaging mode. The techniques involved range from full-field microscopy, to reach the widest fields of view (>mm), to ptychography, to achieve the highest resolution (<100 nm), and have been implemented at the I13 Coherence Branchline at Diamond Light Source.

scholarly journals Development and Validation of an X-ray Imaging Detector for Digital Radiography at Low Resolution

2020 ◽  
Vol 7 (2) ◽  
pp. 181-187
Author(s):  
Abdiel Ramírez Reyes ◽  
Gerardo Herrera Corral ◽  
Elsa Ordoñez Casanova ◽  
Héctor Alejandro Trejo Mandujano ◽  
Uzziel Caldiño Herrera
Keyword(s):  
Detection System ◽  
X Rays ◽  
Modulation Transfer ◽  
Resolution Limit ◽  
Large Area ◽  
X Ray ◽  
Regular Type ◽  
Digital Radiographs ◽  
Ccd Sensor ◽  
X Ray Imaging

Digital X-ray detectors are required in different sciences and applications, however many high quality devices are expensive although high-resolution images are not always required. We present an easy way to build a detector capable of forming X-ray digital images and video with a very large area (18×18 cm2). The detector is formed by three main components: scintillator, optics lenses and CCD sensor. Basically, the device converts the X-rays into visible light which is then collected by the CCD sensor. The scintillator is Gadox type, from Carestream®, 18×18 cm2, regular type, lambda 547 nm. The optics lenses are generic, with manual focus and widely visual field. The CCD sensor has a size of 1/3″, 752 × 582 pixels, monochrome, 20 FPS, 12 bits ADC and pixel size of 3.8 μm. With the built detector and an X-ray source, we formed an X-ray imaging detection system to generate digital radiographs of biological or inert objects-examples are given-, as well as real-time X-ray video. Additionally, the spatial resolution limit was measured in terms of Modulation Transfer Function by the method of opaque edge from a lead sheet with a result of 1.1 Lp/mm. Finally using a filter, the focal spot of the X-ray source is measured, resulting in a diameter of 0.9 mm (FWHM).

scholarly journals COMPUTED TOMOGRAPHY OF CRYOGENIC CELLS

2002 ◽  
Vol 09 (01) ◽  
pp. 177-183 ◽  
Author(s):  
G. SCHNEIDER ◽  
E. ANDERSON ◽  
S. VOGT ◽  
C. KNÖCHEL ◽  
D. WEISS ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Damage ◽  
Three Dimensional ◽  
Numerical Aperture ◽  
X Rays ◽  
Full Field ◽  
X Ray ◽  
Specific Proteins ◽  
Male Specific ◽  
In Cells

Soft X-ray microscopy has resolved 30 nm structures in biological cells. To protect the cells from radiation damage caused by X-rays, imaging of the samples has to be performed at cryogenic temperatures, which makes it possible to take multiple images of a single cell. Due to the small numerical aperture of zone plates, X-ray objectives have a depth of focus on the order of several microns. By treating the X-ray microscopic images as projections of the sample absorption, computed tomography (CT) can be performed. Since cryogenic biological samples are resistant to radiation damage, it is possible to reconstruct frozen-hydrated cells imaged with a full-field X-ray microscope. This approach is used to obtain three-dimensional information about the location of specific proteins in cells. To localize proteins in cells, immunolabeling with strongly X-ray absorbing nanoparticles was performed. With the new tomography setup developed for the X-ray microscope XM-1 installed at the ALS, we have performed tomography of immunolabeled frozen-hydrated cells to detect protein distributions inside of cells. As a first example, the distribution of the nuclear protein male-specific lethal 1 (MSL-1) in the Drosophila melanogaster cell was studied.

Defects of Platelet Function Recognized by X-Ray Imaging and Scanning Electron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 610-613
Author(s):  
M.G. Baldini ◽  
S. Morinaga ◽  
D. Minasian ◽  
R. Feder ◽  
D. Sayre ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Biology ◽  
Imaging Technique ◽  
Human Platelets ◽  
X Rays ◽  
X Ray ◽  
X Ray Imaging ◽  
Complex Phenomena ◽  
Scanning Electron

Contact X-ray imaging is presently developing as an important imaging technique in cell biology. Our recent studies on human platelets have demonstrated that the cytoskeleton of these cells contains photondense structures which can preferentially be imaged by soft X-ray imaging. Our present research has dealt with platelet activation, i.e., the complex phenomena which precede platelet appregation and are associated with profound changes in platelet cytoskeleton. Human platelets suspended in plasma were used. Whole cell mounts were fixed and dehydrated, then exposed to a stationary source of soft X-rays as previously described. Developed replicas and respective grids were studied by scanning electron microscopy (SEM).

Comparison of high-angle take-off and low-angle take-off EDX detector geometry of the HF-2000 FE-TEM

1993 ◽  
Vol 51 ◽  
pp. 252-253
Author(s):  
Y. Sato ◽  
T. Hashimoto ◽  
M. Ichihashi ◽  
Y. Ueki ◽  
K. Hirose ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Field Emission ◽  
Solid Angle ◽  
Energy Dispersive ◽  
Objective Lens ◽  
X Rays ◽  
High Angle ◽  
X Ray ◽  
Detector Geometry

Analytical TEMs have two variations in x-ray detector geometry, high and low angle take off. The high take off angle is advantageous for accuracy of quantitative analysis, because the x rays are less absorbed when they go through the sample. The low take off angle geometry enables better sensitivity because of larger detector solid angle.Hitachi HF-2000 cold field emission TEM has two versions; high angle take off and low angle take off. The former allows an energy dispersive x-ray detector above the objective lens. The latter allows the detector beside the objective lens. The x-ray take off angle is 68° for the high take off angle with the specimen held at right angles to the beam, and 22° for the low angle take off. The solid angle is 0.037 sr for the high angle take off, and 0.12 sr for the low angle take off, using a 30 mm2 detector.

An investigation into the extent of Lodox imaging usage in South Africa: Radiographer’s perspective

2021 ◽  
Author(s):  
Julius Muchui Thambura ◽  
Jeanette G.E du Plessis ◽  
Cheryl M E McCrindle ◽  
Tanita Cronje
Keyword(s):  
South Africa ◽  
Waiting Times ◽  
Cross Sectional Study ◽  
Trauma Patients ◽  
X Rays ◽  
Online Questionnaire ◽  
Cross Sectional ◽  
Imaging Protocol ◽  
X Ray ◽  
X Ray Imaging

Abstract Introduction Anecdotal evidence suggests that medical professionals in trauma units are requesting additional regional images using conventional x-ray systems, even after trauma patients have undergone full-body Lodox scans. Patients are then exposed to additional radiation, additional waiting times and an increased medical bill. This study aimed at investigating the extent to which Lodox systems were used in trauma units (n=28) in South Africa. Method In this descriptive cross-sectional study, the researcher invited one radiographer from the 28 hospitals in South Africa that use Lodox systems. Radiographers who were most experienced in using the Lodox system completed an online questionnaire. Results Twenty (71.43% n=20) out of twenty-eight radiographers responded. Most hospitals (90%, n=18) were referring patients for additional conventional x-ray images. Radiographers indicated that conventional x-rays were requested for the chest (27.80%, 10/36), the abdomen (16.67%, 6/36), the spine (13.89%, 5/36) and the extremities and skull (19.44%, 7/36). Additionally, radiographers reported using Lodox to perform procedures and examinations usually performed on conventional x-ray systems when conventional x-ray systems were not operational. Conclusion Currently, it is not clear if the use of conventional x-ray imaging following Lodox is necessary, but the results suggest that the practice is commonplace, with healthcare workers in most hospitals (90%, n=18) requesting additional x-ray imaging. The researcher thus recommends that an imaging protocol for Lodox imaging systems should be developed to guide the referral of the patients for further imaging.

scholarly journals Truncated Inception Net: COVID-19 Outbreak Screening using Chest X-rays

2020 ◽  
Author(s):  
Dipayan Das ◽  
KC Santosh ◽  
Umapada Pal
Keyword(s):  
Neural Network ◽  
World Wide ◽  
Imaging Techniques ◽  
Imaging Systems ◽  
Ct Scans ◽  
X Rays ◽  
X Ray ◽  
X Ray Imaging ◽  
Proposed Model ◽  
Different Types

Abstract Since December 2019, the Coronavirus Disease (COVID-19) pandemic has caused world-wide turmoil in less than a couple of months, and the infection, caused by SARS-CoV-2, is spreading at an unprecedented rate. AI-driven tools are used to identify Coronavirus outbreaks as well as forecast their nature of spread, where imaging techniques are widely used, such as CT scans and chest X-rays (CXRs). In this paper, motivated by the fact that X-ray imaging systems are more prevalent and cheaper than CT scan systems, a deep learning-based Convolutional Neural Network (CNN) model, which we call Truncated Inception Net, is proposed to screen COVID-19 positive CXRs from other non-COVID and/or healthy cases. To validate our proposal, six different types of datasets were employed by taking the following CXRs: COVID-19 positive, Pneumonia positive, Tuberculosis positive, and healthy cases into account. The proposed model achieved an accuracy of 99.96% (AUC of 1.0) in classifying COVID- 19 positive cases from combined Pneumonia and healthy cases. Similarly, it achieved an accuracy of 99.92% (AUC of 0.99) in classifying COVID-19 positive cases from combined Pneumonia, Tuberculosis and healthy CXRs. To the best of our knowledge, as of now, the achieved results outperform the existing AI-driven tools for screening COVID-19 using CXRs.

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