The ions are generated and collected in the storage ion source, mass selected in the quadrupole mass filter 1 and then stored in the 22-pole ion trap. This trap, consisting of 22 RF-electrodes forming a cylindrical structure (see inset), is mounted on a closed cycle helium refrigerator. On entrance, the ions are cooled down to the ambient cryogenic temperature (15 K) by a short intense helium pulse. During the storage period, the ions are subject to reactive gases. After the desired storage time, all parent and product ions are extracted into the quadrupole mass filter 2 and the selected mass is counted on the Daly detector. ...less