High resolution, large spectral range, in variable-included-angle soft X-ray monochromators using a plane VLS grating

2005 ◽  
Vol 538 (1-3) ◽  
pp. 760-770 ◽  
Author(s):  
Ruben Reininger ◽  
A.R.B. de Castro
Keyword(s):  
High Resolution ◽  
Spectral Range ◽  
Included Angle ◽  
X Ray

Photoemission Measurements Of Photocathode Materials In The 115–400 Å Range

1993 ◽  
Vol 306 ◽  
Author(s):  
S. Grantham ◽  
M.C. Richardson ◽  
R. Watts ◽  
T. Lucatorto ◽  
C. Tarrio ◽  
...  
Keyword(s):  
High Resolution ◽  
Ultraviolet Radiation ◽  
Water Absorption ◽  
Spectral Range ◽  
Storage Time ◽  
Prolonged Exposure ◽  
Alkali Halides ◽  
X Ray ◽  
Hygroscopic Nature ◽  
Similar Materials

AbstractWith the intent of finding a sensitive photocathode material in the 130 Å (100eV) X-ray range for use in a high resolution soft X-ray Conversion Microscope, photoelectron yields of several materials (mostly alkali halides), were measured at the National Institute of Standards and Technology's (NIST) Synchrotron Ultraviolet Radiation Facility II (SURF II). These measurements were made as a function of wavelength in the spectral range 115 Å-400 Å. The measured values are comparable to previous measurements of the photoelectron yields of these and similar materials, and to an existing model of photoemission [1–3]. We also determined the effects of prolonged exposure to X-ray light on performance. Moreover, because of the hygroscopic nature of Alkali Iodides, measurements of the photoelectron yield versus wavelength were repeated for samples of CsI that were kept in storage for periods of time to determine the effects of storage time and water absorption on the photoelectron yield.

scholarly journals HgMn Stars as Apparent X-Ray Emitters

1998 ◽  
Vol 188 ◽  
pp. 217-218 ◽  
Author(s):  
S. Hubrig ◽  
T. W. Berghöfer
Keyword(s):  
High Resolution ◽  
Spectral Range ◽  
Spectral Type ◽  
Late Type ◽  
X Ray ◽  
Sky Survey ◽  
Low Mass ◽  
Almost All ◽  
Einstein Observatory

In the ROSAT all-sky survey 11 HgMn stars were detected as soft X-ray emitters (Berghöfer, Schmitt & Cassinelli 1996). Prior to ROSAT, X-ray observations with the Einstein Observatory had suggested that stars in the spectral range B5-A7 are devoid of X-ray emission. Since there is no X-ray emitting mechanism available for these stars (also not for HgMn stars), the usual argument in the case of an X-ray detected star of this spectral type is the existence of an unseen low-mass companion which is responsible for the X-ray emission. However, this hypothesis is not easily testable. Based on high resolution X-ray images taken with the ROSAT HRI, Berghöfer & Schmitt (1994) showed that known visual late-type companions can be disregarded in this context. In almost all cases studied so far (including two HgMn stars in our sample) the X-ray emission is associated with the primary B star.

scholarly journals An XMM-Newton view of a small sample of Seyfert, 1 Galaxies

2010 ◽  
Vol 6 (S274) ◽  
pp. 369-372
Author(s):  
M. V. Cardaci ◽  
G. F. Hagele ◽  
M. Santos-Lleó ◽  
Y. Krongold ◽  
A. I. Díaz ◽  
...  
Keyword(s):  
High Resolution ◽  
Emission Line ◽  
Detailed Analysis ◽  
Spectral Range ◽  
Small Sample ◽  
Continuum Emission ◽  
Absorption And Emission ◽  
X Ray ◽  
Line Features ◽  
The Continuum

AbstractWe present a detailed analysis of all the X-ray data taken by the XMM-Newton satellite of a small sample of five Seyfert 1 galaxies: ESO 359-G19, HE 1143-1810, CTS A08.12, Mkn 110, and UGC 11763. Our aim is to characterize the different components of the material that print the absorption and emission features in the X-ray spectra of these objects. The continuum emission was studied through the EPIC spectra taking advantage of the spectral range of these cameras. The high resolution RGS spectra were analyzed in order to characterize the absorbing features and the emission line features that arise in the spectra of these sources.

scholarly journals Multilayer Mirror Based High-Resolution Solar Soft X-Ray Spectrometer

2021 ◽  
Vol 8 ◽  
Author(s):  
S. S. Panini ◽  
S. Narendranath ◽  
P. Sreekumar ◽  
K. Sankarasubramanian
Keyword(s):  
High Resolution ◽  
Spectral Range ◽  
Spectral Resolution ◽  
High Spectral Resolution ◽  
High Resolution Spectroscopy ◽  
Time Variability ◽  
Type I ◽  
The Sun ◽  
X Rays ◽  
X Ray

Soft X-ray spectroscopy of the Sun is an important tool to understand the coronal dynamics and composition. The solar coronal X-ray spectrum below 1 keV is the least explored with high-resolution spectroscopy. Recent observations with Hinode XRT using coarse spectroscopy along with high-resolution imaging have shown that abundances in the coronae have variability associated with structures on the Sun. Disk averaged abundances with better spectral resolution spectrometers show time variability associated with flares. Both spatial and temporal variabilities seem to be related to changes in the magnetic field topology. Understanding such short term variabilities is necessary to model the underlying dynamics and mixing of material between different layers of the Sun. A Sensitive high-resolution spectrometer that covers the range in plasma temperatures and emission line complexes would uniquely reveal the entire evolution of flares. We are investigating a design of a multi-layer mirror-based X-ray spectrograph in the spectral range from 0.5 to 7 keV. The instrument operates in four asynchronous spectral channels operating one at a time. The multi-layer mirror placed at the focus of a Wolter type I telescope reflects a narrow band X-rays to the CCD which is placed at Nasmyth defocus. Converging X-rays from the front end optics helps to increase the spectral range of each channel while preserving the spectral resolution. This design is estimated to achieve a spectral resolution of 20 eV in the spectral range of 0.5–7 keV. With such high spectral resolution, we can resolve individual spectral features e.g., 6.7 keV Fe complex which can be used to diagnose high-temperature transient plasma during flares. The instrument design estimated performance and the science capabilities of this instrument will be discussed in detail in the paper.

Electron microscopy of rabbit FC crystals

1983 ◽  
Vol 41 ◽  
pp. 730-731
Author(s):  
Robert A. Grant ◽  
Laura L. Degn ◽  
Wah Chiu ◽  
John Robinson
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Molecular Replacement ◽  
X Ray ◽  
X Ray Crystallography ◽  
Resolution Electron ◽  
Replacement Technique ◽  
Hydrated Crystal ◽  
Molecular Structure Analysis

Proteolytic digestion of the immunoglobulin IgG with papain cleaves the molecule into an antigen binding fragment, Fab, and a compliment binding fragment, Fc. Structures of intact immunoglobulin, Fab and Fc from various sources have been solved by X-ray crystallography. Rabbit Fc can be crystallized as thin platelets suitable for high resolution electron microscopy. The structure of rabbit Fc can be expected to be similar to the known structure of human Fc, making it an ideal specimen for comparing the X-ray and electron crystallographic techniques and for the application of the molecular replacement technique to electron crystallography. Thin protein crystals embedded in ice diffract to high resolution. A low resolution image of a frozen, hydrated crystal can be expected to have a better contrast than a glucose embedded crystal due to the larger density difference between protein and ice compared to protein and glucose. For these reasons we are using an ice embedding technique to prepare the rabbit Fc crystals for molecular structure analysis by electron microscopy.

High Resolution Study of Polytypism: Application to SiC and Au3 Mn

1982 ◽  
Vol 40 ◽  
pp. 540-541
Author(s):  
G. Van Tendeloo ◽  
J. Van Landuyt ◽  
S. Amelinckx
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Stacking Sequence ◽  
X Ray ◽  
Powerful Technique ◽  
Resolution Study ◽  
The Ideal

Polytypism has been studied for a number of years and a wide variety of stacking sequences has been detected and analysed. SiC is the prototype material in this respect; see e.g. Electron microscopy under high resolution conditions when combined with x-ray measurements is a very powerful technique to elucidate the correct stacking sequence or to study polytype transformations and deviations from the ideal stacking sequence.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

Scanning Electron Microscopy and x-ray analysis of microparticles and early hydration effects

1995 ◽  
Vol 53 ◽  
pp. 692-693
Author(s):  
Yun Lu ◽  
David C. Joy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Morphological Development ◽  
Early Hydration ◽  
X Ray ◽  
Blended Cements ◽  
Powder Particles ◽  
Chemical Wastes ◽  
Scanning Electron

High resolution scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) were performed to investigate microparticles in blended cements and their hydration products containing sodium-rich chemical wastes. The physical appearance of powder particles and the morphological development at different hydration stages were characterized by using high resolution SEM Hitachi S-900 and by SEM S-800 with a EDX spectrometer. Microparticles were dispersed on the sample holder and glued by 1% palomino solution. Hydrated bulk samples were dehydrated by acetone and mounted on the holder by silver paste. Both fracture surfaces and flat cutting sections of hydrating samples were prepared and examined. Some specimens were coated with an 3 nm thick Au-Pd or Cr layer to provide good conducting surfaces. For high resolution SEM S-900 observations the accelerating voltage of electrons was 1-2 KeV to protect the electron charging. Microchemical analyses were carried out by S800/EDS equipped with a LINK detector of take-off angle =40°.

Tubulin structure at intermediate resolution

1995 ◽  
Vol 53 ◽  
pp. 852-853
Author(s):  
K. H. Downing ◽  
S. G. Wolf ◽  
E. Nogales
Keyword(s):  
High Resolution ◽  
Structural Data ◽  
Therapeutic Drug ◽  
Zinc Ions ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Negative Stain ◽  
Functional Mechanisms ◽  
Tubulin Structure

Microtubules are involved in a host of critical cell activities, many of which involve transport of organelles through the cell. Different sets of microtubules appear to form during the cell cycle for different functions. Knowledge of the structure of tubulin will be necessary in order to understand the various functional mechanisms of microtubule assemble, disassembly, and interaction with other molecules, but tubulin has so far resisted crystallization for x-ray diffraction studies. Fortuitously, in the presence of zinc ions, tubulin also forms two-dimensional, crystalline sheets that are ideally suited for study by electron microscopy. We have refined procedures for forming the sheets and preparing them for EM, and have been able to obtain high-resolution structural data that sheds light on the formation and stabilization of microtubules, and even the interaction with a therapeutic drug.Tubulin sheets had been extensively studied in negative stain, demonstrating that the same protofilament structure was formed in the sheets and microtubules. For high resolution studies, we have found that the sheets embedded in either glucose or tannin diffract to around 3 Å.

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