Velocity map imaging of ions and electrons using electrostatic lenses: Application in photoelectron and photofragment ion imaging of molecular oxygen

Eppink, André T. J. B.; Parker, David H.

doi:doi:10.1063/1.1148310

Volume/Page
Keyword
DOI
Citation
Advanced

Volume: Page/Article:

Search Content Type

article doi:

Citation:

A transmission x-ray microscope based on secondary-electron imaging

A design for a transmission x-ray microscope with 20 nm transverse spatial resolution is presented. The microscope, which is based on the electron-optical imaging of the photoemitted electrons from an x-ray shadowgraph, consists of a transmission x-ray photocathode coupled to a photoelectron emission microscope (PEEM—also called a PEM for photoelectron microscope). Unlike the conventional PEEM, which produces a surface map of photoelectron yield, this microscope can provide information on the s...

Data acquisition system to interface between imaging instruments and the network: Applications in electron microscopy and ultrasound

A system for data acquisition for imaging instruments utilizing a computer network was created. Two versions of this system, both with the same basic design, were separately installed in conjunction with an electron microscope and a clinical ultrasound device. They serve the functions of data acquisition and data server to manage and to transfer images from these instruments. The virtues of this system are its simplicity of design, universality, cost effectiveness, ease of management, security ...

The application of electrostatic lenses is demonstrated to give a substantial improvement of the two-dimensional (2D) ion/electron imaging technique. This combination of ion lens optics and 2D detection makes “velocity map imaging” possible, i.e., all particles with the same initial velocity vector are mapped onto the same point on the detector. Whereas the more common application of grid electrodes leads to transmission reduction, severe trajectory deflections and blurring due to the non-point source geometry, these problems are avoided with open lens electrodes. A three-plate assembly with aperture electrodes has been tested and its properties are compared with those of grid electrodes. The photodissociation processes occurring in molecular oxygen following the two-photon 3dπ(³Σ1g−)(v = 2, N = 2)←X(³Σg−) Rydberg excitation around 225 nm are presented here to show the improvement in spatial resolution in the ion and electron images. Simulated trajectory calculations show good agreement with experiment and support the appealing properties of this velocity mapping technique. © 1997 American Institute of Physics.

RELATED DATABASES

To view database links for this article, you need to log in.

KEYWORDS and PACS

Keywords

electrostatic lenses, ion optics, electron optics, electron lenses, particle velocity analysis, oxygen, photodissociation, photoemission, two-photon processes, Rydberg states

PACS

41.85.Ne

Electrostatic lenses, septa
33.80.Gj

Diffuse spectra; predissociation, photodissociation
33.60.+q

Photoelectron spectra
33.80.Rv

Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states)