Cold and Hot Slumped Glass Optics with interfacing ribs for high angular resolution x-ray telescopes

It has been long known that orientation effects in crystalline materials can influence characteristic x-ray emission and microanalysis1-7. High Angular Resolution Electron Channeling X-ray Spectroscopy (HARECXS)6-7. a variation of ALCHEMI4-5, has been used at ANL for the last few years to investigate the effects of channeling on quantitative XEDS analysis of materials. More recently we have also been using HARECXS to carefully measure elemental disordering in a number of systems and have found that it can be used very successfully to elucidate the various stages of disorder.Perovskite (nominally CaTiO3) is a host phase for actinides in various wasteforms for the immobilization of high level radioactive nuclear waste. Over geologic time, alpha decay damage of the actinides in perovskite will cause displacive effects that influence the dimensional and chemical stability of the wasteform. in the past, the progression of damage has been studied by monitoring changes in selected area electron diffraction (SAED) patterns with increasing dose (e.g. 11).

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Electron Channeling X-ray Microanalysis for Cation Configuration in Irradiated Magnesium Aluminate Spinel

MRS Proceedings ◽

10.1557/proc-589-129 ◽

1999 ◽

Vol 589 ◽

Cited By ~ 10

Author(s):

S. Matsumura ◽

T. Soeda ◽

N. J. Zaluzec ◽

C. Kinoshita

Keyword(s):

Angular Resolution ◽

Magnesium Aluminate ◽

High Angular Resolution ◽

X Rays ◽

Magnesium Aluminate Spinel ◽

X Ray ◽

Electron Channeling ◽

Resolution Electron ◽

Practical Tool ◽

Cation Arrangement

AbstractHigh angular resolution electron channeling x-ray spectroscopy (HARECXS) was examined as a practical tool to locate lattice-ions in spinel crystals. The orientation dependent intensity distribution of emitted x-rays obtained by HARECXS is so sensitive to lattice-ion configuration in the illuminated areas that the occupation probabilities on specific positions in the crystal lattice can be determined accurately through comparison with the theoretical rocking curves. HARECXS measurements have revealed partially disordered cation arrangement in MgO·nAl2O3 with n= 1.0 and 2.4. Most A13+ lattice-ions occupy the octahedral (VI) sites with 6-fold coordination, while Mg2+ lattice-ions reside on both the tetrahedral (IV) and the octahedral (VI) sites. The structural vacancies are enriched in the IV-sites. Further evacuation of cations from the IV-sites to the VI-sites is recognized in a disordering process induced by irradiation with 1 MeV Ne+ ions up to 8.9 dpa at 870 K.

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Avalanche photodiode arrays for a high-angular resolution X-ray and gamma-ray imaging telescopes

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/j.nima.2007.06.034 ◽

2007 ◽

Vol 580 (2) ◽

pp. 848-852 ◽

Cited By ~ 2

Author(s):

M.R. Squillante ◽

R.A. Myers ◽

F. Robertson ◽

R. Farrell ◽

J.F. Christian ◽

...

Keyword(s):

Gamma Ray ◽

Angular Resolution ◽

Avalanche Photodiode ◽

High Angular Resolution ◽

X Ray ◽

Gamma Ray Imaging ◽

Photodiode Arrays ◽

Imaging Telescopes

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The Huber G670 imaging-plate Guinier camera tested on beamline I711 at the MAX II synchrotron

Journal of Applied Crystallography ◽

10.1107/s0021889800000893 ◽

2000 ◽

Vol 33 (2) ◽

pp. 394-396 ◽

Cited By ~ 23

Author(s):

Kenny Ståhl

Keyword(s):

Angular Resolution ◽

High Angular Resolution ◽

Imaging Plate ◽

Correction Factors ◽

Synchrotron Source ◽

X Ray ◽

Synchrotron Beam ◽

Unusual Combination ◽

Low Symmetry ◽

Collection Time

A Huber G670 imaging-plate Guinier powder diffraction camera has been tested at an X-ray synchrotron source. It was found to be a very potent tool, offering an unusual combination of high angular resolution and short data collection time, while using very small amounts of sample. Specifically, it was found that: (i) the angular resolution (full width at half-maximum) varies between 0.07 and 0.15° in 2θ without focusing,i.e.relying on a parallel synchrotron beam; (ii) with a readout and erasure cycle time of 15 s, it is possible to obtain Rietveld-refinable data within less than a minute for a low-symmetry zeolite refined with 82 parameters; (iii) special attention has to be given to calibration of the detector and some general geometrical correction factors should be included in the data reduction.

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HARECX Measurements of Electron Channeling Effects on Quantitative AEM-Based XEDS

Microscopy and Microanalysis ◽

10.1017/s1431927600037181 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 938-939

Author(s):

Nestor J. Zaluzec

Keyword(s):

Angular Resolution ◽

High Angular Resolution ◽

Crystalline Materials ◽

X Ray ◽

Electron Channeling ◽

Resolution Electron ◽

Analytical Electron ◽

Analytical Electron Microscope ◽

Tem Mode ◽

Impurity Elements

It has been long known that orientation effects in crystalline materials can influence characteristic x-ray emission and microanalysis. Most of the recent studies have concentrated upon using the phenomenon to perform site specific distributions of impurity elements in ordered compounds using the ALCHEMI methodology. For the most part, it has been asserted that increasing the parameters of thickness, orientation and beam convergence effectively averages out these effects. Using High Angular Resolution Electron Channeling X-ray Spectroscopy (HARECXS) we have carefully measured the phenomenon in a number of ordered systems and find that it must be considered in many cases.All experimental measurements presented here were conducted on a Philips EM 420T analytical electron microscope. The instrument was operated in the TEM mode, at 120 kV using a LaB6 electron source. The characteristic x-ray emission was measured using an ED AX ultra thin window Si(Li) detector having a FWHM of ∼ 145 eV at Mn Ka.

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Deconvolving the Nucleus of Centaurus A Using Chandra PSF Library

Symposium - International Astronomical Union ◽

10.1017/s0074180900220445 ◽

2001 ◽

Vol 205 ◽

pp. 66-69

Author(s):

Margarita Karovska ◽

T. Aldcroft ◽

M.S. Elvis ◽

I.N. Evans ◽

G. Fabbiano ◽

...

Keyword(s):

Black Hole ◽

Angular Resolution ◽

High Angular Resolution ◽

Central Source ◽

X Ray ◽

Preliminary Results ◽

Multi Scale ◽

Supermassive Black Hole ◽

Scale Structures ◽

Centaurus A

We describe preliminary results from our study of multi-scale structures in Centaurus A (NGC 5128) obtained using the Chandra X-ray Observatory HRC-I observations. The high-angular resolution Chandra images reveal X-ray multi-scale structures in this object with unprecedented detail and clarity. The region surrounding the Cen A nucleus, believed to be associated with a supermassive black hole, shows structures on arcsecond scales clearly resolved from the central source.

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