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HK: Physik der Hadronen und Kerne

HK 17: Nuclear Physics / Spectroscopy II

HK 17.2: Gruppenbericht

Dienstag, 12. März 2002, 17:15–17:45, B

High-accuracy mass measurements on N=Z nuclei using ISOLTRAP — •Frank Herfurth¹, F. Ames², G. Audi³, D. Beck⁴, K. Blaum⁴, G. Bollen⁵, A. Kellerbauer¹, H.-J. Kluge⁴, D. Lunney³, R.B. Moore⁶, D. Rodrígez⁴, E. Sauvan¹, C. Scheidenberger⁴, S. Schwarz⁵, G. Sikler⁴, C. Weber⁴, and the ISOLDE-Collaboration¹ — ¹CERN, Geneva — ²LMU, Munich — ³CSNSM, Orsay — ⁴GSI, Darmstadt — ⁵NSCL, East Lansing — ⁶McGill Univ., Montreal

ISOLTRAP is a Penning trap mass spectrometer installed at the on-line mass separator ISOLDE at CERN/Geneva. It serves for high-accuracy mass measurements of radioactive nuclides by determining their cyclotron frequency. After high-accuracy mass measurements on ⁷⁴Rb, ⁷⁴Kr and ³⁴Ar, the mass of ³²Ar was measured recently. A relative uncertainty below 10⁻⁷ was reached despite the short half-life of only 98 ms. This mass value is needed in the context of the search for scalar contributions to the standard model of weak interactions [1]. The experimental Q_EC value for the ³²Ar superallowed β decay has now the required uncertainty of only a few keV. ⁷²Kr is one of the two waiting point nuclei that define the speed of the astrophysical rp-process beyond A=64. Among other things, its mass is an important input for the correct understanding and modeling of the rp-process in this region. The mass of ⁷²Kr was measured with a relative uncertainty of about 10⁻⁷.

[1] E. G. Adelberger et al., Phys. Rev. Lett. 83, 1299 and 3101 (1999).