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MS: Fachverband Massenspektrometrie

MS 7: Poster

MS 7.8: Poster

Mittwoch, 21. März 2007, 16:30–18:30, Poster A

Recent high-precision mass measurements on radionuclides with the Penning trap mass spectrometer ISOLTRAP — •Alexander Herlert — CERN, Physics Department, 1211 Geneva 23, Switzerland – for the ISOLTRAP Collaboration

With the Penning trap mass spectrometer ISOLTRAP the masses of short-lived Al, Ca, Mn, Fe, Cd, and Ag isotopes have been measured in 2006. The masses of ²⁶Al and ³⁸Ca contribute as input values for a test of the unitarity of the CKM quark mixing matrix. Since the absolute mass uncertainty needs to be well below 1 keV, a new Ramsey excitation scheme with time-separated rf excitation fields has been applied, leading to a higher precision for the determination of the cyclotron frequency. For the neutron-rich Ag isotopes, isomers were present in the ISOLDE beam. By application of a dipolar excitation either the ground state or the isomeric state was selected for the investigation [1]. Especially for ¹¹⁸Ag only the isomeric state has been investigated. In case of the Mn isotopes the in-trap decay method [2] has been applied in order to produce neutron-rich Fe isotopes which are in general not available at the ISOLDE facility. To this end, Mn ions with mass A=61−63 have been stored for one second in the preparation Penning trap and the corresponding Fe ions were created by beta decay and stored after buffer gas cooling and centering before being transferred to the precision trap for mass measurement. An overview of the results and an update of technical developments are presented.

[1] K. Blaum et al., Europhys. Lett. 67, 586 (2004)
[2] A. Herlert et al., New J. Phys. 7, 44 (2005)