scholarly journals Absolute, high-accuracy characterization of a variable line spacing grating for the European XFEL soft X-ray monochromator

2017 ◽  
Vol 25 (22) ◽  
pp. 26519 ◽  
Author(s):  
Maurizio Vannoni ◽  
Idoia Freijo-Martin
2013 ◽  
Vol 21 (1) ◽  
pp. 273-279 ◽  
Author(s):  
L. Xue ◽  
R. Reininger ◽  
Y.-Q. Wu ◽  
Y. Zou ◽  
Z.-M. Xu ◽  
...  

A new ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline has been designed and is under construction at the Shanghai Synchrotron Radiation Facility. The beamline has two branches: one dedicated to angle-resolved photoemission spectroscopy (ARPES) and the other to photoelectron emission microscopy (PEEM). The two branches share the same plane-grating monochromator, which is equipped with four variable-line-spacing gratings and covers the 20–2000 eV energy range. Two elliptically polarized undulators are employed to provide photons with variable polarization, linear in every inclination and circular. The expected energy resolution is approximately 10 meV at 1000 eV with a flux of more than 3 × 1010 photons s−1at the ARPES sample positions. The refocusing of both branches is based on Kirkpatrick–Baez pairs. The expected spot sizes when using a 10 µm exit slit are 15 µm × 5 µm (horizontal × vertical FWHM) at the ARPES station and 10 µm × 5 µm (horizontal × vertical FWHM) at the PEEM station. The use of plane optical elements upstream of the exit slit, a variable-line-spacing grating and a pre-mirror in the monochromator that allows the influence of the thermal deformation to be eliminated are essential for achieving the ultrahigh-energy resolution.


2018 ◽  
Vol 43 (18) ◽  
pp. 4390 ◽  
Author(s):  
Zhong Yin ◽  
Heike Löchel ◽  
Jens Rehanek ◽  
Claudia Goy ◽  
Anton Kalinin ◽  
...  
Keyword(s):  
X Ray ◽  

Author(s):  
Jun Qian ◽  
Jonathan Manton ◽  
Sunil Bean ◽  
Peter Takacs ◽  
Lahsen Assoufid ◽  
...  
Keyword(s):  
X Ray ◽  

2011 ◽  
Vol 18 (2) ◽  
pp. 134-142 ◽  
Author(s):  
V. N. Strocov ◽  
T. Schmitt ◽  
U. Flechsig ◽  
L. Patthey ◽  
G. S. Chiuzbăian

2019 ◽  
Vol 26 (5) ◽  
pp. 1782-1789 ◽  
Author(s):  
Dakui Lin ◽  
Zhengkun Liu ◽  
Kay Dietrich ◽  
Andréy Sokolov ◽  
Mewael Giday Sertsu ◽  
...  

A fabrication method comprising near-field holography (NFH) with an electron beam lithography (EBL)-written phase mask was developed to fabricate soft X-ray varied-line-spacing gratings (VLSGs). An EBL-written phase mask with an area of 52 mm × 30 mm and a central line density greater than 3000 lines mm−1 was used. The introduction of the EBL-written phase mask substantially simplified the NFH optics for pattern transfer. The characterization of the groove density distribution and diffraction efficiency of the fabricated VLSGs indicates that the EBL–NFH method is feasible and promising for achieving high-accuracy groove density distributions with corresponding image properties. Vertical stray light is suppressed in the soft X-ray spectral range.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.


Author(s):  
L. T. Germinario

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.


Author(s):  
J. H. Resau ◽  
N. Howell ◽  
S. H. Chang

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5 Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.


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