Super-resolution photoelectron imaging with real-time subpixelation by field programmable gate array and its application to NO and benzene photoionization

Yoshihiro Ogi, Hiroshi Kohguchi, Dongmei Niu, Keijiro Ohshimo, Toshinori Suzuki

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

We have constructed a photoelectron imaging spectrometer with super-resolution image processing and have applied it to the photoionization of nitric oxide and benzene in molecular beams. A field programmable gate array is employed for real-time subpixel centroiding calculations on hardware, providing 64 megapixel resolution (8192 × 8192 pixels). We examined eight different centroiding algorithms based on the center-of-gravity (COG) and Gaussian fitting (Gauss) methods and have found that the two-dimensional COG (2D-COG) and weighted mean of Gaussian center (w-Gauss) methods have the best performance. The excellent performance of the instrument is demonstrated by visualizing a 25 μm diameter pore structure of an MCP, indicating a spatial resolution of 0.03%. The photoelectron image in one-color (1 + 1) resonance-enhanced multiphoton ionization of nitric oxide using a nanosecond laser provided a photoelectron kinetic energy resolution of 0.2%. This resolution is currently restricted by charged-particle optics. The photoelectron energy and angular distributions in the one-color (1 + 1) resonance-enhanced multiphoton ionization of benzene via 61 and 6111 vibronic levels in the Si state are also presented. The results demonstrate that photoelectron angular anisotropy varies with the photoelectron kinetic energy and the vibronic state of the cation.

Original languageEnglish
Pages (from-to)14536-14544
Number of pages9
JournalJournal of Physical Chemistry A
Volume113
Issue number52
DOIs
Publication statusPublished - 2009 Dec 31
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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