Carbon clusters for absolute mass measurements at ISOLTRAP

The cyclotron frequencies of singly charged carbon clusters C(n)(+) (n > 2) were measured with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The present limit of mass accuracy deltam/m = 1.2.10(-8) and the extent of the mass-dependent systematic shift (deltam/m)(sys) = 1.7(0.6) . 10(-10)/u . (m - m(ref)) of the setup were investigated for the first time. In addition, absolute mass measurements by use of pure clusters of the most abundant carbon isotope (12)C are now possible at ISOLTRAP.