A time-of-flight electron spectrometer for studies of forward electron emission in ion–atom collisions

Abstract

We describe a time-of-flight electron spectrometer designed for measurements of the energy spectra of the electrons emitted in the forward direction in ion–atom collisions. The most important part of the spectrometer is an electrostatic mirror. The electrons ejected in a small angular range (typically ±1°) around 0° from a gas jet target by a well-collimated ion beam are reflected by the mirror into backward angles. Following the reflection, the electrons fly in a field-free space until they reach the detector. The time-of-flight of the electrons elapsed between their emission and detection is measured by detecting the electrons in coincidence with the charge-state analysed outgoing projectiles. Results of test measurements carried out for collisions of 200–350 keV Cq+ (q = 1, 2) ions with Ar atoms are presented.