Phase-sensitive radial extraction and mass spectrometry of trapped ions in a compact geometry

The detection of trapped atomic and molecular ions of rubidium, by extraction, from our thin-wire electrode-modified spherical Paul trap, is discussed in detail. The compact geometry poses serious challenges and constraints for efficient extraction and reliable detection of ions. The solution to the dual challenge of counting the trapped ions with minimum pileup loss as well as detection that permits reliable mass spectroscopy is experimentally implemented. The details of the ion extraction process are understood by numerical simulation. The experimental and numerical data are compared and found to be in close agreement. The reliability of the technique for future, multi-species experiments, is established, and possible improvements are discussed.