Description of the third-order optical aberrations of near-circular pupil optical systems without symmetry

2005 ◽  
Vol 22 (7) ◽  
pp. 1389 ◽  
Author(s):  
Kevin Thompson
Keyword(s):  
Optical Systems ◽  
Optical Aberrations ◽  
Third Order ◽  
The Third

Method of calculating the aberrations of soft X-ray and vacuum ultraviolet optical systems

2019 ◽  
Vol 26 (5) ◽  
pp. 1558-1564
Author(s):  
Yiqing Cao ◽  
Zhijuan Shen ◽  
Zhixia Zheng
Keyword(s):  
Optical System ◽  
Vacuum Ultraviolet ◽  
Optical Systems ◽  
Third Order ◽  
Order Accuracy ◽  
X Ray ◽  
Plane Symmetric ◽  
The Third ◽  
Aberration Theory ◽  
Ray Coordinates

Based on the the third-order aberration theory of plane-symmetric optical systems, this paper studies the effect on aberrations of the second-order accuracy of aperture-ray coordinates and the extrinsic aberrations of this kind of optical system; their calculation expressions are derived. The resultant aberration expressions are then applied to calculate the aberrations of two design examples of soft X-ray and vacuum ultraviolet (XUV) optical systems; images are compared with ray-tracing results using SHADOW software to validate the aberration expressions. The study shows that the accuracy of the aberration expressions is satisfactory.

A modified Ion Slit Lens for virtual Variation of Slit Widths

1960 ◽  
Vol 15 (4) ◽  
pp. 350-355 ◽  
Author(s):  
A. J. H. Boerboom
Keyword(s):  
Mass Spectrometer ◽  
Original System ◽  
Slit Width ◽  
Resolving Power ◽  
Peak Shape ◽  
Lens System ◽  
Optical Aberrations ◽  
Third Order ◽  
The Third ◽  
Zero Potential

It is shown that a slit lens system, already known in literature and used in mass spectrometer collector systems to vary the resolving power, can be greatly improved by introducing a potential on one of the electrodes, which previously was at zero potential. The focusing at the collector is unaltered within optical aberrations of the third order and the range of adjustment is increased as compared with the original system. Experimentally it was found that the virtual collector slit width could be adjusted from 1 mm down to 0.15 mm, maintaining a fair peak shape.

Probe size and 5th-order aberration

1987 ◽  
Vol 45 ◽  
pp. 134-135 ◽  
Author(s):  
Zhifeng Shao
Keyword(s):  
Electron Probe ◽  
Spherical Aberration ◽  
Wave Length ◽  
Cylindrical Symmetry ◽  
Electron Wave ◽  
Third Order ◽  
The Third ◽  
Probe Radius ◽  
Small Probe ◽  
Probe Size

A small electron probe has many applications in many fields and in the case of the STEM, the probe size essentially determines the ultimate resolution. However, there are many difficulties in obtaining a very small probe.Spherical aberration is one of them and all existing probe forming systems have non-zero spherical aberration. The ultimate probe radius is given byδ = 0.43Csl/4ƛ3/4where ƛ is the electron wave length and it is apparent that δ decreases only slowly with decreasing Cs. Scherzer pointed out that the third order aberration coefficient always has the same sign regardless of the field distribution, provided only that the fields have cylindrical symmetry, are independent of time and no space charge is present. To overcome this problem, he proposed a corrector consisting of octupoles and quadrupoles.

Children’s Recall of Approximations to English

1973 ◽  
Vol 16 (2) ◽  
pp. 201-212 ◽  
Author(s):  
Elizabeth Carrow ◽  
Michael Mauldin
Keyword(s):  
Language Development ◽  
Fourth Order ◽  
Third Order ◽  
Memory Processes ◽  
The Third ◽  
General Index ◽  
General Linguistic

As a general index of language development, the recall of first through fourth order approximations to English was examined in four, five, six, and seven year olds and adults. Data suggested that recall improved with age, and increases in approximation to English were accompanied by increases in recall for six and seven year olds and adults. Recall improved for four and five year olds through the third order but declined at the fourth. The latter finding was attributed to deficits in semantic structures and memory processes in four and five year olds. The former finding was interpreted as an index of the development of general linguistic processes.

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