Experimental method for determination of the integral cross-section for electron impact ionization of ions with optical control of the target’s initial quantum state

Abstract

A method for measurement of integral cross-sections for electron impact ionization of ions is proposed. The technique involves the application of a quadrupole ion trap with laser-cooled ions. It allows controlling the initial quantum state of the target ions, measuring the cross-sections separately for such states. The methodology is described in detail, together with a discussion of the reliability of optical selection of the ions’ states. The first results for Ca+ ion ionization from 42S1/2 and 32D3/2 states are presented.