HIGH-RESOLUTION MASS-SPECTROMETRY OF LIGHT-IONS IN A PENNING TRAP

After a brief introduction to the electromagnetic ion trap, we concent rate on the problems related to precise determination of cyclotron fre quencies of stored ions. Since these frequency measurements are perfor med in order to obtain mass ratios we want to point out the inherent d ifficulties in detecting mass ratios different from 1.0. We then descr ibe the time-of-flight method of detecting ion cyclotron resonance sig nals. With a small room temperature Penning trap of characteristic siz e d=1.8 mm in a 7 T magnetic field we study the effect of changing ele ctrical field anharmonicities (i.e. dodecapole term) and of various to n numbers on the cyclotron frequency.