R K SINGH, R K MOHANTA, M J SINGH¹, R HIPPLER², S K GOEL³ and R SHANKER

Atomic Physics Laboratory, Physics Department, Banaras Hindu University, Varanasi 221 005, India
¹  Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382 428, India
²  Fachbereich Physik, Universitaet Greifswald, Domstrasse 10a, 17487 -- Greifswald, Germany
³  Technology Information, Forecasting and Assessment  Council (TIFAC), DST, New Delhi 110 016, India
Email: rshanker@banaras.ernet.in

 Abstract.

A time-of-flight spectrometer has been designed and fabricated for measuring the charge state distributions of target ions produced in collisions of keV-electrons with gaseous target atoms/molecules. The design details of the spectrometer and the description of experimental procedures for optimizing various parameters are presented and discussed. The working principle of the spectrometer, its time- and mass-focussing conditions, transmissions and detection efficiency etc. are given. A few typical test runs on multiple ionization of Ne and Ar gas atoms are illustrated. These spectra are found to yield the time resolution of about 10 ns for Ar⁴⁺ ion peak in 24.0 keV e^- -- Ar collisions while the mass resolution of the spectrometer is obtained about 10% at mass m = 20.  

Keywords:  Recoil ions; time-of-flight (TOF) spectrometer; multiple ionization.

Pacs Nos.  29.25.-t; 34.70.+e