High-resolution computer-controlled monochromator system for fiber diffraction grating measurements

2000 ◽  
Author(s):  
Jerzy Helsztynski ◽  
Wieslaw Jasiewicz ◽  
Kazimierz P. Jedrzejewski ◽  
Lech Lewandowski ◽  
Krzysztof T. Pozniak
Keyword(s):  
High Resolution ◽  
Diffraction Grating ◽  
Fiber Diffraction ◽  
Computer Controlled

Computer-Controlled Hrem Alignment Using Automated Diffractogram Analysis

1990 ◽  
Vol 48 (1) ◽  
pp. 532-533
Author(s):  
G.Y. Fan ◽  
O.L. Krivanek
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
The Other ◽  
Full Information ◽  
Resolution Electron ◽  
Skilled Operator ◽  
Automatic Alignment ◽  
High Resolution Electron Microscope ◽  
Computer Controlled ◽  
Recorded Image

Full alignment of a high resolution electron microscope (HREM) requires five parameters to be optimized: the illumination angle (beam tilt) x and y, defocus, and astigmatism magnitude and orientation. Because neither voltage nor current centering lead to the correct illumination angle, all the adjustments must be done on the basis of observing contrast changes in a recorded image. The full alignment can be carried out by a computer which is connected to a suitable image pick-up device and is able to control the microscope, sometimes with greater precision and speed than even a skilled operator can achieve. Two approaches to computer-controlled (automatic) alignment have been investigated. The first is based on measuring the dependence of the overall contrast in the image of a thin amorphous specimen on the relevant parameters, the other on measuring the image shift. Here we report on our progress in developing a new method, which makes use of the full information contained in a computed diffractogram.

scholarly journals High Resolution X-ray Spectroscopy: Is It Interesting? Is It Possible?

2005 ◽  
Vol 13 ◽  
pp. 790-792
Author(s):  
Webster Cash
Keyword(s):  
High Resolution ◽  
High Throughput ◽  
Spectral Resolution ◽  
Diffraction Grating ◽  
High Efficiency ◽  
X Ray ◽  
New Science

AbstractThe diffraction grating spectra from Chandra and XMM-Newton have given the astronomical community a huge step forward in x-ray spectroscopy of celestial sources. They have proven the scientific richness of the field. But the spectra have resolution of only 300 to 1000 – low by the standards of the visible and the ultraviolet. We discuss some of the exciting new science that can be addressed if spectral resolution of up to 10,000 (or more) can be achieved in the x-ray. We then show how practical, high efficiency, high resolution x-ray spectrographs can be built for high throughput missions like Constellation-X and XEUS.

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