Precise Atomic Masses for Fundamental Physics Determined at SMILETRAP

Precise Atomic Masses for Fundamental Physics Determined at SMILETRAP 

During this time the question was raised whether a crystal of Si could be used as an atomic definition of the kilogram. Therefore a measurement of the mass of this atom was made using singly charged silicon ions and and ions as mass references [6]. Though we reached a statistical uncertainty of 10 we had to face the large q/A asymmetry which resulted in a systematic uncertainty of 10 .  

This was a clear warning that in future mass measurements we should use ions which, as close as possible, are q/A doublets. Nevertheless, at that time, it was a tenfold improvemenf of fhe Si mass. Later in Stockholm, using fully stripped Si ions, we could reach a mass uncertainty of 3.5 x 10 [7], a compatible value, with a somewhat higher accuracy, had been obtained by the MIT-group [8]. 

A further highlight from SMILETRAP is the determination of the Ge double /3-decay Q-value [11,12]. This is important to identify the energy where one could observe possible events of neutrinoless double /3-decay that can occur if the neutrino is a Majorana particle. 

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