Bochum 1998 – wissenschaftliches Programm
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HK: Hadronen und Kerne
HK 64: Radii, Masses, Heavy Nuclei
HK 64.2: Vortrag
Donnerstag, 19. März 1998, 14:30–14:45, E
Highly Accurate Mass Measurements of Mercury and Rare Earth Isotopes with the ISOLTRAP Spectrometer — •A. Kohl1, D. Beck1, F. Herfurth1, H.-J. Kluge1, S. Schwarz1, G. Audi2, D. Lunney2, M. de Saint Simon2, R.B. Moore3, F. Ames4, P. Schmidt4, I. Martel Bravo5, Y. Jading6, G. Bollen6, and the ISOLDE-Collaboration6 — 1GSI, Darmstadt — 2CSNSM, Orsay — 3McGill Univ., Montreal — 4J. Gutenberg Univ., Mainz — 5CSIC, Madrid — 6CERN, Genf
The mass spectrometer ISOLTRAP at the on-line separator ISOLDE/CERN serves for highly accurate mass measurements of radioactive isotopes. The 60keV ion beam delivered by ISOLDE is captured and accumulated in a Paul trap ion beam buncher. Subsequently the ions are transfered to the cooler trap of the tandem Penning trap spectrometer. A mass selective buffer gas cooling process with a resolving power of ≈ 105 serves for the separation of isobars. Then the cooled ions are transported to the precision trap in which the mass determination takes place via the measurement of the cyclotron frequency of the ions. A resolving power of up to ≈ 3 · 106 and an accuracy of δ m m ≈ 1 · 10−7 is reached. The latest measurements were carried out on neutron deficient mercury and rare earth isotopes in the vicinity of 146Gd. Important for these measurements was the possibility to separate isobars and to resolve ground and isomeric states. The latter is even possible for low excitation energies as demonstrated in the case of 185Hg (ΔE =103 keV).