Development of a Low Energy Ion Mass Spectrometer

Abstract

<p> The interaction mechanisms of an ion beam with a solid target are identified. Basic parameters associated with ion scattering, charge neutralization, inelastic energy losses and secondary ion production are described. Low energy (1-20 kev) experimental studies on these topics are reviewed. A low energy ion mass spectrometer is described. The ion beam is generated by an existing kev ion accelerator and is directed to a newly constructed UHV target chamer. The energy and angular distributions of the backscattered particles are measured with a hemispherical electrostatic analyser and a channeltron detector. A high precision goniometer allows target rotation about two perpendicular axes by angles of 180° and 90° with an accuracy and repeatability of 0.1°. The interaction chamber is bakeable to 250°c and was designed for an ultimate pressure of 10^-11 torr. The data acquisition system chamber scans the energy spectrum automatically so that the radiation dosage at the target is equalized for all channels. </p>