Finite slice analysis (FINA) of sliced and velocity mapped images on a Cartesian grid
| Autor: | Chandika Amarasinghe, S. Y. T. van de Meerakker, N. Rombes, Arthur G. Suits, Casey D. Foley, James O. F. Thompson, Sjoerd N. Vogels, Zhi Gao |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
010304 chemical physics business.industry Spectroscopy of Cold Molecules Mathematical analysis General Physics and Astronomy 02 engineering and technology Image segmentation Image plane 021001 nanoscience & nanotechnology 01 natural sciences Finite element method Regular grid law.invention Optics law 0103 physical sciences Cartesian coordinate system Cylindrical coordinate system Physical and Theoretical Chemistry Polar coordinate system 0210 nano-technology Projection (set theory) business |
| Zdroj: | Journal of Chemical Physics, 147, 7, pp. 1-9 Journal of Chemical Physics, 147, 1-9 |
| ISSN: | 0021-9606 |
| Popis: | Although time-sliced imaging yields improved signal-to-noise and resolution compared with unsliced velocity mapped ion images, for finite slice widths as encountered in real experiments there is a loss of resolution and recovered intensities for the slow fragments. Recently, we reported a new approach that permits correction of these effects for an arbitrarily sliced distribution of a 3D charged particle cloud. This finite slice analysis (FinA) method utilizes basis functions that model the out-of-plane contribution of a given velocity component to the image for sequential subtraction in a spherical polar coordinate system. However, the original approach suffers from a slow processing time due to the weighting procedure needed to accurately model the out-of-plane projection of an anisotropic angular distribution. To overcome this issue we present a variant of the method in which the FinA approach is performed in a cylindrical coordinate system (Cartesian in the image plane) rather than a spherical polar coordinate system. Dubbed C-FinA, we show how this method is applied in much the same manner. We compare this variant to the polar FinA method and find that the processing time (of a 510 × 510 pixel image) in its most extreme case improves by a factor of 100. We also show that although the resulting velocity resolution is not quite as high as the polar version, this new approach shows superior resolution for fine structure in the differential cross sections. We demonstrate the method on a range of experimental and synthetic data at different effective slice widths. |
| Databáze: | OpenAIRE |
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