PRECISION MASS MEASUREMENTS USING A PENNING TRAP AND HIGHLY-CHARGED IONS PRODUCED IN AN ELECTRON-BEAM ION-SOURCE

A method for precision mass measurements in a Penning trap using highl y charged ions produced in an electron beam ion source (CRYSIS) has be en developed. The cyclotron frequencies for O-8+,O- 7+,O- 6+,O- 5+ and Ar-18+,Ar- 17+,Ar- 16+,Ar- 15+,Ar- 14+,Ar- 13+ ions have been determi ned by the excitation of the sum frequency nu+ + nu-. In addition to C RYSIS ions, H+, H-2(+) and He+ ions were produced by electron bombardm ent of the Hz rest gas or helium gas introduced through an UHV leak va lve into an auxiliary ion trap (or a pre-trap). A technique for fast ( seconds) interchanging of the ion species in the precision trap has be en implemented to reduce the long term magnetic field drift.