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MS: Massenspektrometrie
MS 5: Präzisions-MS kurzlebiger Nuklide 1
MS 5.4: Talk
Wednesday, March 15, 2006, 15:00–15:15, H1
Optimization of the cyclotron frequency determination forhigh-accuracy mass measurements on short-lived radionuclides — •Michael Dworschak1, Klaus Blaum2,3, Sebastian George2,3, Alexander Herlert4, and Chabouh Yazidjian2,4 — 1Bayerische Julius-Maximilians-Universität, 97070Würzburg, Germany — 2GSI Darmstadt, 64291 Darmstadt,Germany — 3Institut für Physik, JohannesGutenberg-Universität Mainz, 55099 Mainz, Germany — 4Physics Department, CERN, 1211 Geneva 23, Switzerland
The mass is a fundamental property of a nuclide. Its measurement contributes to a variety of fundamental studies including tests of the Standard Model and the weak interaction. The limits of mass measurements of exotic nuclei have been extended considerably by improving and developing the Penning trap mass spectrometer ISOLTRAP at the ISOLDE facility at CERN. The mass resolving power of ISOLTRAP reaches 107 and the uncertainty of the resulting mass values has been pushed down to 8·10−9. The mass is determined by measuring the cyclotron frequency of the stored ion. To reduce the measurement uncertainty a number of improvements in ion detection and data taking have been developed. One of them is analyzing the weights of the individual frequency points of the resonance curve from which the cyclotron frequency is determined. By measuring only selected frequency points the uncertainty could be reduced by a factor of two. In addition, it was essential to implement a temperature stabilization system at the level of a few mK for the trap setup, in order to minimize magnetic field fluctuations.