scholarly journals Procedures for cryogenic X-ray ptychographic imaging of biological samples

IUCrJ ◽  
2017 ◽  
Vol 4 (2) ◽  
pp. 147-151 ◽  
Author(s):  
M. Yusuf ◽  
F. Zhang ◽  
B. Chen ◽  
A. Bhartiya ◽  
K. Cunnea ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Light Source ◽  
Biological Samples ◽  
Biological Sample ◽  
Experimental Setup ◽  
X Rays ◽  
Human Chromosomes ◽  
X Ray ◽  
Cryogenic Conditions

Biological sample-preparation procedures have been developed for imaging human chromosomes under cryogenic conditions. A new experimental setup, developed for imaging frozen samples using beamline I13 at Diamond Light Source, is described. This manuscript describes the equipment and experimental procedures as well as the authors' first ptychographic reconstructions using X-rays.

scholarly journals Linearly polarized X-ray fluorescence computed tomography based on a Thomson scattering light source: a Monte Carlo study

2020 ◽  
Vol 27 (3) ◽  
pp. 737-745
Author(s):  
Zhijun Chi ◽  
Yingchao Du ◽  
Wenhui Huang ◽  
Chuanxiang Tang
Keyword(s):  
Computed Tomography ◽  
Monte Carlo ◽  
Compton Scattering ◽  
Light Source ◽  
Thomson Scattering ◽  
X Rays ◽  
X Ray ◽  
Pile Up ◽  
Linearly Polarized ◽  
Scattering Light

A Thomson scattering X-ray source can provide quasi-monochromatic, continuously energy-tunable, polarization-controllable and high-brightness X-rays, which makes it an excellent tool for X-ray fluorescence computed tomography (XFCT). In this paper, we examined the suppression of Compton scattering background in XFCT using the linearly polarized X-rays and the implementation feasibility of linearly polarized XFCT based on this type of light source, concerning the influence of phantom attenuation and the sampling strategy, its advantage over K-edge subtraction computed tomography (CT), the imaging time, and the potential pulse pile-up effect by Monte Carlo simulations. A fan beam and pinhole collimator geometry were adopted in the simulation and the phantom was a polymethyl methacrylate cylinder inside which were gadolinium (Gd)-loaded water solutions with Gd concentrations ranging from 0.2 to 4.0 wt%. Compared with the case of vertical polarization, Compton scattering was suppressed by about 1.6 times using horizontal polarization. An accurate image of the Gd-containing phantom was successfully reconstructed with both spatial and quantitative identification, and good linearity between the reconstructed value and the Gd concentration was verified. When the attenuation effect cannot be neglected, one full cycle (360°) sampling and the attenuation correction became necessary. Compared with the results of K-edge subtraction CT, the contrast-to-noise ratio values of XFCT were improved by 2.03 and 1.04 times at low Gd concentrations of 0.2 and 0.5 wt%, respectively. When the flux of a Thomson scattering light source reaches 1013 photons s−1, it is possible to finish the data acquisition of XFCT at the minute or second level without introducing pulse pile-up effects.

A scanning transmission X-ray microscope at the Pohang Light Source

2018 ◽  
Vol 25 (3) ◽  
pp. 878-884 ◽  
Author(s):  
Hyun-Joon Shin ◽  
Namdong Kim ◽  
Hee-Seob Kim ◽  
Wol-Woo Lee ◽  
Chae-Soon Lee ◽  
...  
Keyword(s):  
Energy Range ◽  
Light Source ◽  
Photon Energy ◽  
Chemical State ◽  
Photon Energy Range ◽  
X Rays ◽  
X Ray ◽  
Space Resolution ◽  
Scanning Transmission ◽  
Pohang Light Source

A scanning transmission X-ray microscope is operational at the 10A beamline at the Pohang Light Source. The 10A beamline provides soft X-rays in the photon energy range 100–2000 eV using an elliptically polarized undulator. The practically usable photon energy range of the scanning transmission X-ray microscopy (STXM) setup is from ∼150 to ∼1600 eV. With a zone plate of 25 nm outermost zone width, the diffraction-limited space resolution, ∼30 nm, is achieved in the photon energy range up to ∼850 eV. In transmission mode for thin samples, STXM provides the element, chemical state and magnetic moment specific distributions, based on absorption spectroscopy. A soft X-ray fluorescence measurement setup has been implemented in order to provide the elemental distribution of thicker samples as well as chemical state information with a space resolution of ∼50 nm. A ptychography setup has been implemented in order to improve the space resolution down to 10 nm. Hardware setups and application activities of the STXM are presented.

The Munich Compact Light Source: initial performance measures

2016 ◽  
Vol 23 (5) ◽  
pp. 1137-1142 ◽  
Author(s):  
Elena Eggl ◽  
Martin Dierolf ◽  
Klaus Achterhold ◽  
Christoph Jud ◽  
Benedikt Günther ◽  
...  
Keyword(s):  
Light Source ◽  
Large Scale ◽  
Source Size ◽  
Relativistic Electrons ◽  
X Rays ◽  
Beam Hardening ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
Compact Light Source

While large-scale synchrotron sources provide a highly brilliant monochromatic X-ray beam, these X-ray sources are expensive in terms of installation and maintenance, and require large amounts of space due to the size of storage rings for GeV electrons. On the other hand, laboratory X-ray tube sources can easily be implemented in laboratories or hospitals with comparatively little cost, but their performance features a lower brilliance and a polychromatic spectrum creates problems with beam hardening artifacts for imaging experiments. Over the last decade, compact synchrotron sources based on inverse Compton scattering have evolved as one of the most promising types of laboratory-scale X-ray sources: they provide a performance and brilliance that lie in between those of large-scale synchrotron sources and X-ray tube sources, with significantly reduced financial and spatial requirements. These sources produce X-rays through the collision of relativistic electrons with infrared laser photons. In this study, an analysis of the performance, such as X-ray flux, source size and spectra, of the first commercially sold compact light source, the Munich Compact Light Source, is presented.

scholarly journals A lathe system for micrometre-sized cylindrical sample preparation at room and cryogenic temperatures

2020 ◽  
Vol 27 (2) ◽  
pp. 472-476
Author(s):  
Mirko Holler ◽  
Johannes Ihli ◽  
Esther H. R. Tsai ◽  
Fabio Nudelman ◽  
Mariana Verezhak ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Room Temperature ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Cylindrical Sample ◽  
X Ray ◽  
X Ray Computed ◽  
Cryogenic Conditions ◽  
Cylindrical Samples ◽  
Potential Use

A simple two-spindle based lathe system for the preparation of cylindrical samples intended for X-ray tomography is presented. The setup can operate at room temperature as well as under cryogenic conditions, allowing the preparation of samples down to 20 and 50 µm in diameter, respectively, within minutes. Case studies are presented involving the preparation of a brittle biomineral brachiopod shell and cryogenically fixed soft brain tissue, and their examination by means of ptychographic X-ray computed tomography reveals the preparation method to be mainly free from causing artefacts. Since this lathe system easily yields near-cylindrical samples ideal for tomography, a usage for a wide variety of otherwise challenging specimens is anticipated, in addition to potential use as a time- and cost-saving tool prior to focused ion-beam milling. Fast sample preparation becomes especially important in relation to shorter measurement times expected in next-generation synchrotron sources.

Performance of BL07A at NewSUBARU with installation of a new multi-layered-mirror monochromator

2021 ◽  
Vol 28 (2) ◽  
pp. 618-623
Author(s):  
Shotaro Tanaka ◽  
Shuto Suzuki ◽  
Tomohiro Mishima ◽  
Kazuhiro Kanda
Keyword(s):  
Synchrotron Radiation ◽  
Energy Range ◽  
Light Source ◽  
Monochromatic Light ◽  
High Vacuum ◽  
Photon Flux ◽  
X Rays ◽  
Monochromatic Beam ◽  
X Ray ◽  
High Photon Flux

Soft X-rays excite the inner shells of materials more efficiently than any other form of light. The investigation of synchrotron radiation (SR) processes using inner-shell excitation requires the beamline to supply a single-color and high-photon-flux light in the soft X-ray region. A new integrated computing multi-layered-mirror (MLM) monochromator was installed at beamline 07A (BL07A) of NewSUBARU, which has a 3 m undulator as a light source for irradiation experiments with high-photon-flux monochromatic light. The MLM monochromator has a high reflectivity index in the soft X-ray region; it eliminates unnecessary harmonic light from the undulator and lowers the temperature of the irradiated sample surfaces. The monochromator can be operated in a high vacuum, and three different mirror pairs are available for different experimental energy ranges; they can be exchanged without exposing the monochromator to the atmosphere. Measurements of the photon current of a photodiode on the sample stage indicated that the photon flux of the monochromatic beam was more than 1014 photons s−1 cm−2 in the energy range 80–400 eV and 1013 photons s−1 cm−2 in the energy range 400–800 eV. Thus, BL07A is capable of performing SR-stimulated process experiments.

scholarly journals Development of ultrafast capabilities for X-ray free-electron lasers at the linac coherent light source

2019 ◽  
Vol 377 (2145) ◽  
pp. 20180386 ◽  
Author(s):  
Ryan N. Coffee ◽  
James P. Cryan ◽  
Joseph Duris ◽  
Wolfram Helml ◽  
Siqi Li ◽  
...  
Keyword(s):  
Light Source ◽  
Free Electron ◽  
Cross Correlation ◽  
X Rays ◽  
Coherent Light ◽  
High Brightness ◽  
X Ray ◽  
Linac Coherent Light Source ◽  
Optical Laser ◽  
Coherent Light Source

The ability to produce ultrashort, high-brightness X-ray pulses is revolutionizing the field of ultrafast X-ray spectroscopy. Free-electron laser (FEL) facilities are driving this revolution, but unique aspects of the FEL process make the required characterization and use of the pulses challenging. In this paper, we describe a number of developments in the generation of ultrashort X-ray FEL pulses, and the concomitant progress in the experimental capabilities necessary for their characterization and use at the Linac Coherent Light Source. This includes the development of sub-femtosecond hard and soft X-ray pulses, along with ultrafast characterization techniques for these pulses. We also describe improved techniques for optical cross-correlation as needed to address the persistent challenge of external optical laser synchronization with these ultrashort X-ray pulses. This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays’.

LIGA Technologies and Applications

MRS Bulletin ◽  
2001 ◽  
Vol 26 (4) ◽  
pp. 337-340 ◽  
Author(s):  
Jill Hruby
Keyword(s):  
Synchrotron Radiation ◽  
Methyl Methacrylate ◽  
Light Source ◽  
High Energy ◽  
X Rays ◽  
Electromechanical Systems ◽  
X Ray ◽  
Poly Methyl Methacrylate

LIGA, an acronym for the German words for lithography, electroplating, and molding, is a technique used to produce micro-electromechanical systems (MEMS) made from metals, ceramics, or plastics. The LIGA process utilizes x-ray synchrotron radiation as a lithographic light source. Highly collimated, high-energy x-rays from the synchrotron impinge on a patterned mask in proximity to an x-ray-sensitive photoresist, typically poly(methyl methacrylate) (PMMA).

scholarly journals Imaging local electric fields produced upon synchrotron X-ray exposure

2014 ◽  
Vol 112 (3) ◽  
pp. 696-701 ◽  
Author(s):  
Christopher M. Dettmar ◽  
Justin A. Newman ◽  
Scott J. Toth ◽  
Michael Becker ◽  
Robert F. Fischetti ◽  
...  
Keyword(s):  
Electric Fields ◽  
Second Harmonic ◽  
Soft Materials ◽  
Local Fields ◽  
X Rays ◽  
Electron Hole ◽  
X Ray ◽  
X Ray Absorption ◽  
Static Electric Fields ◽  
Cryogenic Conditions

Electron–hole separation following hard X-ray absorption during diffraction analysis of soft materials under cryogenic conditions produces substantial local electric fields visualizable by second harmonic generation (SHG) microscopy. Monte Carlo simulations of X-ray photoelectron trajectories suggest the formation of substantial local electric fields in the regions adjacent to those exposed to X-rays, indicating a possible electric-field–induced SHG (EFISH) mechanism for generating the observed signal. In studies of amorphous vitreous solvents, analysis of the SHG spatial profiles following X-ray microbeam exposure was consistent with an EFISH mechanism. Within protein crystals, exposure to 12-keV (1.033-Å) X-rays resulted in increased SHG in the region extending ∼3 μm beyond the borders of the X-ray beam. Moderate X-ray exposures typical of those used for crystal centering by raster scanning through an X-ray beam were sufficient to produce static electric fields easily detectable by SHG. The X-ray–induced SHG activity was observed with no measurable loss for longer than 2 wk while maintained under cryogenic conditions, but disappeared if annealed to room temperature for a few seconds. These results provide direct experimental observables capable of validating simulations of X-ray–induced damage within soft materials. In addition, X-ray–induced local fields may potentially impact diffraction resolution through localized piezoelectric distortions of the lattice.

A SOFT X-RAY UNDULATOR BEAMLINE AT THE ADVANCED LIGHT SOURCE WITH CIRCULAR AND VARIABLE LINEAR POLARIZATION FOR THE SPECTROSCOPY AND MICROSCOPY OF MAGNETIC MATERIALS

2002 ◽  
Vol 09 (01) ◽  
pp. 549-554 ◽  
Author(s):  
ANTHONY T. YOUNG ◽  
ELKE ARENHOLZ ◽  
JUN FENG ◽  
HOWARD PADMORE ◽  
STEVE MARKS ◽  
...  
Keyword(s):  
Light Source ◽  
National Laboratory ◽  
X Rays ◽  
X Ray ◽  
Advanced Light Source ◽  
Linearly Polarized ◽  
Linearly Polarized Radiation ◽  
Elliptically Polarized ◽  
Photoemission Electron ◽  
Polarized Radiation

A new undulator beamline at the Advanced Light Source, Lawrence Berkeley National Laboratory is described. This new beamline has an Apple II type undulator which produces linearly and elliptically polarized X-rays. A high resolution monochromator directs the radiation to two branchlines. The first branchline is optimized for spectroscopy and accommodates multiple endstations simultaneously. The second branchline features a photoemission electron microscope. A novel feature of the beamline is the ability to produce linearly polarized radiation at arbitrary, user-selectable angles. Applications of the new beamline are also described.

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