Measurement of emission-angle-resolved time-of-flight distributions of sputtered Mg+ ions

We describe an experiment designed to perform emission-angle-resolved time-of-flight (TOF) analysis of sputter-ejected secondary ions as well as of laser-postionized sputtered neutral particles. The apparatus includes a rotatable linear TOF mass spectrometer and an electron-cyclotron-resonance (ECR) plasma ion source for the bombardment of the target with a mass-filtered Ar+ ion beam pulse in the keV energy region (ion pulse width about 30 ns). We present emission-angle-resolved time-of-flight spectra of Mg+ secondary ions sputter-ejected from a polycrystalline 24Mg target bombarded at 45 incidence. These TOF spectra also contain additional information on the emission-angle dependence of high energy argon projectiles scattered from the target surface. (orig.)