New atomic masses related to fundamental physics measured with SMILETRAP

Sammanfattning: This thesis describes the recent improvements of the SMILETRAP Penning trap mass spectrometer and a number of interesting high precision mass measurements, which have been performed using the improved apparatus, and are relevant in todays fundamental physics problems. The mass of the hydrogen-like 24,26Mg ions as well as the masses of the hydrogen- and lithium-like 40Ca ions are presented in this work that are indispensable input values when evaluating g-factor measurements of the bound electron. In both cases the uncertainty in the masses was improved by one order of magnitude compared to the literature values known so far.The mass of 7Li has been measured and a new mass value has been obtained with an unprecedented relative uncertainty of 6.3x10-10. A large deviation of 1.1 ?u (160ppb) compared to the literature value has been observed. In order to find the reason of this large deviation and to look for possible systematics we have measured the mass of 4He and 6Li and concluded that the 6Li(n,?)7Li reaction Q-value used in the literature when calculating the 7Li mass is wrong by about 1 keV.The mass difference between 3He and 3H (? m (3H -3He)) is the Q-value of the tritium ?-decay. An accurate knowledge of the tritium Q-value is of importance in the search for a finite rest mass of the electron neutrino.By adding a measurement of the mass of 3He1+ to previous mass measurement of 3H1+ and 3He2+ we have improved our previous Q-value by a factor of 2. At the moment our Q-value is the most accurate and more importantly it is based on the correct atomic mass values.