A high-efficiency and high-spectral-resolution EUV/soft X-ray monochromator based on off-plane diffraction

The most efficient diffraction at a periodic grating structure is expected to take place when the incident radiation can be considered to have been specularly reflected off the inclined part of grooves that are positioned parallel to the trajectory of the incident beam. Very encouraging results for this configuration, in which the diffraction takes place off-plane, have been reported recently for a grating to be used in a spectrometer for space science investigations. This grating provided high efficiency for a relatively large groove density and a large blaze angle. High efficiency was observed even in higher diffraction orders up to the fourth order. Here the performance parameters, especially for the combination of diffraction efficiency and achievable spectral resolution, will be discussed for a grating used in a grazing-incidence plane-grating monochromator for monochromatization of synchrotron radiation in the extreme ultraviolet (EUV) and soft X-ray range with photon energies between 30 eV and 2000 eV. It is found that the instrument can provide competitive spectral resolution in comparison with the use of in-plane diffraction. In the case of comparable spectral resolution, the off-plane diffraction is found to provide superior efficiency.

Download Full-text

On obtaining high spectral resolution in extreme ultraviolet/soft X-ray monochromators operating off-plane diffraction in a divergent incident beam

Journal of Synchrotron Radiation ◽

10.1107/s1600577520011194 ◽

2020 ◽

Vol 27 (6) ◽

pp. 1499-1509

Author(s):

Werner Jark

Keyword(s):

Spectral Resolution ◽

Extreme Ultraviolet ◽

Specular Reflection ◽

Incident Beam ◽

Diffraction Order ◽

Source Size ◽

Resolving Power ◽

High Spectral Resolution ◽

Radiation Beam ◽

X Ray

When the trajectory of an incident beam is oriented parallel to the grooves of a periodic grating structure the radiation beam is diffracted off-plane orthogonal to the plane of incidence. The diffraction efficiency in this condition is very high and in a grating with a sawtooth profile it can approach the reflection coefficient for a simple mirror, when the diffraction order of interest follows the direction for specular reflection at the flat part of the steps. When this concept is used in a plane grating in a monochromator for synchrotron radiation sources, the incident beam is almost always collimated in order to minimize any deterioration of the beam properties due to aberrations, which will be introduced in the diffraction process when an uncollimated beam is used. These aberrations are very severe when the groove density is constant. It will be shown that the effect of these aberrations can be corrected after the diffraction by the use of astigmatic focusing. The latter can be provided by a crossed mirror pair with different focal lengths in the corresponding orthogonal directions. Then a monochromator based on this concept can provide source size limited spectral resolution in an uncollimated incident beam. This is identical to the spectral resolution that can be provided by the same grating when operated at the same position in a collimated incident beam. The source size limited spectral resolution in this case corresponds to a high spectral resolving power of better than ΔE/E = 10 000 for photon energies around 300 eV in the soft X-ray range.

Download Full-text

Multilayer X-Ray Optics for Future Missions

Symposium - International Astronomical Union ◽

10.1017/s0074180900115426 ◽

1998 ◽

Vol 188 ◽

pp. 337-338

Author(s):

K. Yamashita ◽

H. Kunieda ◽

Y. Tawara ◽

K. Tamura

Keyword(s):

Spectral Resolution ◽

High Efficiency ◽

Angular Resolution ◽

High Sensitivity ◽

Normal Incidence ◽

Grazing Incidence ◽

Diffraction Limit ◽

Optical Systems ◽

X Ray ◽

Astronomical Imaging

Multilayers have a great potentiality to improve the image quality, spectral resolution and energy coverage of x-ray optical systems. The angular resolution of a normal incidence telescope aims at approaching the diffraction limit in the soft x-ray region. Multilayer supermirror makes it possible to fabricate a grazing incidence telescope with high sensitivity in hard x-ray region. Multilayer coated gratings are also useful dispersive elements with high efficiency and spectral resolution in the 2-10keV region. The application of multilayers is expected to open up a new field in astronomical imaging and spectroscopic observations which are not accessible by present telescopes.

Download Full-text

Rigorous calculations and synchrotron radiation measurements of diffraction efficiencies for tender X-ray lamellar gratings: conical versus classical diffraction

Journal of Synchrotron Radiation ◽

10.1107/s1600577518012419 ◽

2018 ◽

Vol 25 (6) ◽

pp. 1683-1693 ◽

Cited By ~ 4

Author(s):

Leonid Goray ◽

Werner Jark ◽

Diane Eichert

Keyword(s):

Spectral Range ◽

High Efficiency ◽

Promising Result ◽

Surface Profile ◽

Incident Beam ◽

Integral Equation Method ◽

Grazing Incidence ◽

Boundary Integral ◽

Lower Efficiency ◽

X Ray

When reflection gratings are operated at grazing incidence in the extreme off-plane configuration and the incident beam trajectory is parallel to the grooves, the diffraction into the first order can be more efficient than in the classical orientation. This situation is referred to as the conical diffraction case. In the classical configuration the grooves are perpendicular to the incident beam and thus an efficiency-reducing shadowing effect will be observed at very grazing angles. It was recently shown that a laminar grating could provide symmetric and relatively high efficiencies in conical diffraction for diffraction even of photons with large energies of the order of 4 and 6 keV. For photon energies in the tender X-ray range, accurate computing tools for the calculation of diffraction efficiencies from gratings with simple coatings have not been available. Promising results for this spectral range now require the development of tools for modelling the diffraction efficiency expected in optical instrumentation, in which the provision of high efficiency in the indicated spectral range is mandatory. This is the case when weak sources are to be investigated, like in space science. In this study it will be shown that scalar calculations are not appropriate for this purpose, while newly introduced rigorous calculations based on the boundary integral equation method, implemented in the PCGrate ® code, can provide predictions that are in agreement with observed diffraction efficiencies. The agreement is achieved by modelling the exact surface profile. This applies for both the conical diffraction configuration and for the classical in-plane configuration, in which a significantly lower efficiency was obtained. Even though the profile of the presented grating was not perfect, but significantly distorted, the calculations show that efficiency-wise the structure provided already more than 75% of the ideally expected efficiency for conical diffraction. This is a very promising result for further optimization of diffraction gratings for use in the tender X-ray range.

Download Full-text

Comparison of solar soft X-ray irradiance from broadband photometers to a high spectral resolution rocket observation

Advances in Space Research ◽

10.1016/j.asr.2008.10.027 ◽

2009 ◽

Vol 43 (3) ◽

pp. 349-354 ◽

Cited By ~ 3

Author(s):

Thomas N. Woods ◽

Phillip C. Chamberlin

Keyword(s):

Spectral Resolution ◽

High Spectral Resolution ◽

X Ray

Download Full-text

Phase-locked, time-delayed, harmonic pulses for high spectral resolution in the extreme ultraviolet: errata

Optics Letters ◽

10.1364/ol.26.001729 ◽

2001 ◽

Vol 26 (21) ◽

pp. 1729

Author(s):

M. Bellini ◽

S. Cavalieri ◽

C. Corsi ◽

M. Materazzi

Keyword(s):

Spectral Resolution ◽

Extreme Ultraviolet ◽

High Spectral Resolution

Download Full-text

Closely packed, low reorganization energy π-extended postfullerene acceptors for efficient polymer solar cells

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1807535115 ◽

2018 ◽

Vol 115 (36) ◽

pp. E8341-E8348 ◽

Cited By ~ 48

Author(s):

Steven M. Swick ◽

Weigang Zhu ◽

Micaela Matta ◽

Thomas J. Aldrich ◽

Alexandra Harbuzaru ◽

...

Keyword(s):

Solar Cells ◽

Density Functional ◽

High Efficiency ◽

Performance Metrics ◽

Polymer Solar Cells ◽

Reorganization Energy ◽

Grazing Incidence ◽

Scanning Calorimetry ◽

Quantum Chemical Analysis ◽

X Ray

New organic semiconductors are essential for developing inexpensive, high-efficiency, solution-processable polymer solar cells (PSCs). PSC photoactive layers are typically fabricated by film-casting a donor polymer and a fullerene acceptor blend, with ensuing solvent evaporation and phase separation creating discrete conduits for photogenerated holes and electrons. Until recently, n-type fullerene acceptors dominated the PSC literature; however, indacenodithienothiophene (IDTT)-based acceptors have recently enabled remarkable PSC performance metrics, for reasons that are not entirely obvious. We report two isomeric IDTT-based acceptors 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-benz-(5, 6)indanone))-5,5,11,11-tetrakis(4-nonylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]di-thiophene (ITN-C9) and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-benz(6,7)indanone))-5,5,11,11-tetrakis(4-nonylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITzN-C9) that shed light on the exceptional IDTT properties vis-à-vis fullerenes. The neat acceptors and blends with fluoropolymer donor poly{[4,8-bis[5-(2- ethylhexyl)-4-fluoro-2-thienyl]benzo[1,2-b:4,5-b′]dithiophene2,6-diyl]-alt-[2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo4H,8H-benzo[1,2-c:4,5-c′]dithiophene-1,3-diyl]]} (PBDB-TF) are investigated by optical spectroscopy, cyclic voltammetry, thermogravimetric analysis, differential scanning calorimetry, single-crystal X-ray diffraction, photovoltaic response, space-charge-limited current transport, atomic force microscopy, grazing incidence wide-angle X-ray scattering, and density functional theory-level quantum chemical analysis. The data reveal that ITN-C9 and ITzN-C9 organize such that the lowest unoccupied molecular orbital-rich end groups have intermolecular π−π distances as close as 3.31(1) Å, with electronic coupling integrals as large as 38 meV, and internal reorganization energies as small as 0.133 eV, comparable to or superior to those in fullerenes. ITN-C9 and ITzN-C9 have broad solar-relevant optical absorption, and, when blended with PBDB-TF, afford devices with power conversion efficiencies near 10%. Performance differences between ITN-C9 and ITzN-C9 are understandable in terms of molecular and electronic structure distinctions via the influences on molecular packing and orientation with respect to the electrode.

Download Full-text

Refitting an X-ray diffraction system for combined GIXRF and XRR measurements

Powder Diffraction ◽

10.1017/s088571562000041x ◽

2020 ◽

Vol 35 (S1) ◽

pp. S29-S33

Author(s):

Dieter Ingerle ◽

Werner Artner ◽

Klaudia Hradil ◽

Christina Streli

Keyword(s):

Incident Beam ◽

Fluorescence Analysis ◽

Grazing Incidence ◽

Performance Criteria ◽

Nickel Layer ◽

Beam Optics ◽

X Ray Diffraction ◽

X Ray ◽

Special Software ◽

Spectrometer Data

A commercial Empyrean X-ray diffractometer was adapted for combined grazing incidence X-ray fluorescence analysis (GIXRF) measurements with X-ray reflectivity (XRR) measurements. An energy-dispersive silicon drift detector was mounted and integrated in the angle-dependent data acquisition of the Empyrean. Different monochromator/X-ray optics units have been compared with the values obtained by the Atominstitut GIXRF + XRR spectrometer. Data evaluation was performed by JGIXA, a special software for combined GIXRF + XRR data fitting, developed at Atominstitut. A sample consisting of a ~50 nm nickel layer on a silicon substrate was used to compare the performance criteria (i.e. divergence and intensity) of the incident beam optics. An Empyrean X-ray diffractometer was successfully refitted to measure both GIXRF and XRR data.

Download Full-text