A new versatile experimental technique for the study of ion-molecule reacti
ons at very low temperatures is presented. The technique is based upon the
pulsed injection of ions into a uniform and isentropic supersonic expansion
(CRESU experiment). Several ion/molecule reactions have been studied in or
der to test the setup and the reaction between CH+ and CO has been investig
ated under low temperature conditions. (C) 2001 Elsevier Science B.V.