High-resolution field ionizer for state-selective detection of Rydberg atoms in fast-beam laser spectroscopy.

The design of a novel electrode structure for electric-field ionization of Rydberg atoms in a fast atomic beam is described. It allows the resolution of the ion signal from Rydberg atoms with adjacent effective principal quantum numbers n[sup *] in the range of 14≤n[sup *]≤40 and minimizes the volume where field ionization takes place. These features drastically reduce the number of background events arising from collisions of fast atoms with residual gas molecules and thus are essential for trace analysis applications of the technique of resonance ionization spectroscopy in collinear geometry. [ABSTRACT FROM AUTHOR]