Implementation of a position sensitive detection system in a scattered electron-Auger electron coincidence experiment

Abstract

A coincidence data acquisition system, incorporating a position sensitive detector and a custom-built data acquisition card installed in an IBM-PC 486 computer, has been implemented in a coincidence experiment in which scattered electrons and Auger electrons are detected in coincidence. Three analog-to-digital converters (ADCs) are used to digitize all the timing and energy information, and custom-designed and written control software is used to accumulate the data, display it in real time, and store it in expanded memory. The new system has ben used to measure the energy and angular distribution of Auger electrons ejected from argon after electron impact ionization.

Dynamics in electron-impact ionization ofH2O

“…The two analyzers are mounted on independently rotatable turntables which are concentric with the interaction region. The electrons exiting the analyzers are detected by charged particle detectors, with the higherenergy (scattered) electron being detected by a channel electron multiplier, and the low-energy ejected electron being detected by a position-sensitive detector [15]. Coincidence fast timing electronics [15] are used to determine if two detected electrons are correlated (arise from the same scattering event).…”

“…The electrons exiting the analyzers are detected by charged particle detectors, with the higherenergy (scattered) electron being detected by a channel electron multiplier, and the low-energy ejected electron being detected by a position-sensitive detector [15]. Coincidence fast timing electronics [15] are used to determine if two detected electrons are correlated (arise from the same scattering event). The experiments reported here were performed in the coplanar asymmetric geometry, in which the incident and outgoing electrons all lie in the same plane, and the scattered electron is detected at a fixed forward angle, while the ejected electron-energy analyzer is rotated in the plane.…”

Triple-differential cross section for electron-impact ionization of argon in a coplanar symmetric geometry at intermediate energies

“…We have recently replaced the channeltron detector in one of the analyzers with a positionsensitive detector incorporating a pair of microchannel plates with a resistive anode, and the associated rnodi6cations to the data acquisition system have been discussed elsewhere [13].…”