A compact design for velocity-map imaging energetic electrons and ions

TL;DR

This paper introduces a compact velocity-map imaging spectrometer design that enhances energy range and resolution for energetic electrons and ions using minimal additional components.

Contribution

A novel, simplified spectrometer design incorporating an einzel lens to improve energy acceptance and resolution for energetic particles.

Findings

Imaging of electrons up to 65 eV achieved experimentally.

Simulations indicate energy acceptances of <270 and <1,200 eV with high resolution.

Design is compact and uses only two extended electrodes.

Abstract

We present a compact design for a velocity-map imaging spectrometer for energetic electrons and ions. The standard geometry by Eppink and Parker [A. T. J. B. Eppink and D. H. Parker, Rev. Sci. Instrum. 68, 3477 (1997)] is augmented by just two extended electrodes so as to realize an additional einzel lens. In this way, for a maximum electrode voltage of 7 kV we experimentally demonstrate imaging of electrons with energies up to 65 eV. Simulations show that energy acceptances of <270 and <1,200 eV with an energy resolution of dE / E <5% are achievable for electrode voltages of <20 kV when using diameters of the position-sensitive detector of 42 and 78 mm, respectively.