scholarly journals Generation of high brightness x-rays with the PLEIADES Thomson x-ray source

2004 ◽  
Author(s):  
W.J. Brown ◽  
S.G. Anderson ◽  
C.P.J. Barty ◽  
J.K. Crane ◽  
R.R. Cross ◽  
...  
Keyword(s):  
X Rays ◽  
High Brightness ◽  
X Ray

X-Ray absorption edge elemental imaging of B. thuringienis

1989 ◽  
Vol 47 ◽  
pp. 212-213
Author(s):  
R. L. Stears
Keyword(s):  
Absorption Edge ◽  
Elemental Distribution ◽  
X Rays ◽  
Differential Absorption ◽  
Synchrotron Source ◽  
High Brightness ◽  
X Ray ◽  
Elemental Imaging ◽  
Cellular Integrity ◽  
X Ray Absorption

Because of the nature of the bacterial endospore, little work has been done on analyzing their elemental distribution and composition in the intact, living, hydrated state. The majority of the qualitative analysis entailed intensive disruption and processing of the endospores, which effects their cellular integrity and composition.Absorption edge imaging permits elemental analysis of hydrated, unstained specimens at high resolution. By taking advantage of differential absorption of x-ray photons in regions of varying elemental composition, and using a high brightness, tuneable synchrotron source to obtain monochromatic x-rays, contact x-ray micrographs can be made of unfixed, intact endospores that reveal sites of elemental localization. This study presents new data demonstrating the application of x-ray absorption edge imaging to produce elemental information about nitrogen (N) and calcium (Ca) localization using Bacillus thuringiensis as the test specimen.

scholarly journals Use of the Disk-of-least-confusion in X-ray Microanalysis

1998 ◽  
Vol 4 (S2) ◽  
pp. 274-275
Author(s):  
E. A. Kenik ◽  
S. X. Ren
Keyword(s):  
Spatial Resolution ◽  
Electron Scattering ◽  
Electron Probe ◽  
X Rays ◽  
High Brightness ◽  
X Ray ◽  
Electron Sources ◽  
Probe Diameter ◽  
Electron Probe Microanalyzer ◽  
Subsequent Emission

Whereas the spatial resolution for standard secondary electron (SEI) imaging in a scanning electron microscope or electron probe microanalyzer is related to the incident probe diameter, the spatial resolution for x-ray microanalysis is related to the convolution of the probe diameter with the spatial extent of the analyzed volume for a point probe. The latter is determined by electron scattering in the specimen and the subsequent emission of excited x-rays from the specimen. As such, it is possible that “What you see is not what you get”. This is especially true for instruments with high brightness electron sources (field emission). This problem is compounded by probe aberrations which at Gaussian image focus can produce significant electron tails extending tens of microns from the center of the probe.

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’.

scholarly journals X-Ray Microprobe for the Microcharacterization of Materials

1988 ◽  
Vol 143 ◽  
Author(s):  
C. J. Sparks ◽  
G. E. Ice
Keyword(s):  
Energy Deposition ◽  
Materials Science ◽  
Charged Particles ◽  
Chemical Characterization ◽  
X Rays ◽  
High Brightness ◽  
X Ray ◽  
Electron Sources ◽  
Detectable Concentration ◽  
Low Levels

AbstractThe unique properties of X rays offer many advantages over those of electrons and other charged particles for the microcharacterization of materials. X rays are more efficient in exciting characteristic X-ray fluorescence and produce higher fluorescent signal-to-background ratios than obtained with electrons. Detectable limits for X rays are a few parts per billion which are 10−3 to 10−5 lower than for electrons. Energy deposition in the sample from X rays is 10–3 to 10–4 less than for electrons for the same detectable concentration. High-brightness storage rings, especially in the 7 GeV class with undulators, will have sources as brilliant as the most advanced electron probes. The highly collimated X-ray beams from undulators simplify the X-ray optics required to produce submicron X-ray probes with fluxes comparable to electron sources. Such X-ray microprobes will also produce unprecedentedly low levels of detection in diffraction, EXAFS, Auger, and photoelectron spectroscopies for structural and chemical characterization and elemental identification. These major improvements in microcharacterization capabilities will have wide-ranging ramifications not only in materials science but also in physics, chemistry, geochemistry, biology, and medicine.

The NSLS X-1AL scanning x-ray microscope

1993 ◽  
Vol 51 ◽  
pp. 636-637
Author(s):  
Chris Jacobsen ◽  
Janos Kirz ◽  
Steve Lindaas ◽  
Sue Wirick ◽  
Xiaodong Zhang ◽  
...  
Keyword(s):  
Fresnel Zone ◽  
National Laboratory ◽  
Photon Counting ◽  
Brookhaven National Laboratory ◽  
Dark Field ◽  
X Rays ◽  
High Brightness ◽  
X Ray ◽  
Synchrotron Light ◽  
Dose Imaging

Soft x rays are well suited to the study of low-Z elements in 0.1-10 μm thick specimens. A variety of soft x-ray microscopes are now under operation, several of which achieve image resolutions of 0.03-0.1 μm. Scanning x-ray microscopes offer some desirable charactistics: they are able to operate in a variety of imaging modes, including transmission, luminescence, dark field, and photoemission, and they enable minimum dose imaging by utilizing highly efficient photon counting detectors and placing moderate efficiency optics between the source and specimen rather than between specimen and detector.The NSLS X-1AL scanning x-ray microscope uses an undulator at the National Synchrotron Light Source at Brookhaven National Laboratory as a tunable, high-brightness soft x-ray source. Monochromatized, spatially coherent illumination is focussed by a Fresnel zone plate fabricated using electron beam lithography. The sample is scanned through the 0.055 μm Rayleigh resolution focal spot using stepping motors (for large scans) and linearized piezos.

A COMPACT THOMSON X-RAY SOURCE AT SHI

2007 ◽  
Vol 21 (03n04) ◽  
pp. 465-472
Author(s):  
FUMIO SAKAI ◽  
TERUNOBU NAKAJYO ◽  
TATSUYA YANAGIDA ◽  
SHINJI ITO
Keyword(s):  
Laser Pulse Energy ◽  
Laser Light ◽  
Ccd Camera ◽  
Thomson Scattering ◽  
Sapphire Laser ◽  
Relativistic Electrons ◽  
X Rays ◽  
Interaction Point ◽  
High Brightness ◽  
X Ray

A compact, high-brightness x-ray source has been developed through Thomson scattering between photons and relativistic electrons. 33keV energy photons (maximum) were generated in a 165-degree interaction configuration with 38MeV electrons and 800nm-wavelength Ti :sapphire laser light. The number of total photons generated at an interaction point was 106 photons/pulse for a 0.8nC electron bunch charge and 150mJ laser pulse energy. In a 90-degree interaction configuration, 105 photons/pulse total photons were obtained (maximum). Transverse profiles of x-ray intensity and energy were measured by an x-ray CCD camera. These experiment profiles agreed with the analytical results. Imaging using this x-ray source was demonstrated as an application. X-ray images for some objects were taken with various lengths between the objects and the camera. As a result, the refraction contrast images were observed with 17keV x-rays.

The Soft X-ray Scanning Photoemission Microscopy Project at SRRC

1998 ◽  
Vol 5 (3) ◽  
pp. 299-304 ◽  
Author(s):  
Cheng-Hao Ko ◽  
Ruth Klauser ◽  
Der-Hsin Wei ◽  
Hei-Hing Chan ◽  
T. J. Chuang
Keyword(s):  
Distribution System ◽  
Spectroscopic Techniques ◽  
X Rays ◽  
Detection Capability ◽  
Sample Distribution ◽  
High Brightness ◽  
X Ray ◽  
Multichannel Detection ◽  
Radiation Research

The Synchrotron Radiation Research Center (SRRC) and the Institute of Atomic and Molecular Sciences (IAMS) have initiated a project to construct a scanning photoelectron spectromicroscopy end station at SRRC (SRRC-SPEM). High-brightness soft X-rays will be provided by the U5 undulator beamline. Zone-plate-based soft X-ray optics will be used to focus the beam to form the microprobe. A hemispherical sector analyser with multichannel detection capability will collect the photoelectrons. A total of up to 32 images can be acquired concurrently. The apparatus is also equipped with a sample distribution system for in situ sample preparation and characterization in conjunction with other surface spectroscopic techniques.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Chemical Species Identification in an SEM by Changes in Emitted X-Ray Energies

1974 ◽  
Vol 32 ◽  
pp. 570-571
Author(s):  
R. H. Duff
Keyword(s):  
Species Identification ◽  
Valence Electron ◽  
Chemical Species ◽  
X Rays ◽  
Chemical Bonds ◽  
Small Shift ◽  
X Ray ◽  
Electron Transitions ◽  
Peak Energy ◽  
Chemical Combination

A material irradiated with electrons emits x-rays having energies characteristic of the elements present. Chemical combination between elements results in a small shift of the peak energies of these characteristic x-rays because chemical bonds between different elements have different energies. The energy differences of the characteristic x-rays resulting from valence electron transitions can be used to identify the chemical species present and to obtain information about the chemical bond itself. Although these peak-energy shifts have been well known for a number of years, their use for chemical-species identification in small volumes of material was not realized until the development of the electron microprobe.

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