High Precision Atomic Mass Spectrometry with Applications to Neutrino Physics, Fundamental Cosntants and Physical Chemistry

The Florida State University single-ion cryogenic Penning trap mass spectrometer has been used to precisely measure the masses of the doublets 76Ge/76Se and 74Ge/74Se to provide precision Q-values to aid in searches for neutrinoless double beta decay as well as neutrinoless double electron capture. The observation of these processes would provide evidence for the Majorana nature of the electron neutrino and information on neutrino mass. The smallest known â-decay Q-value has also been determined by the measurement of the masses of 115In and 115Sn. The masses of stable alkali isotopes for application as precision mass references as well as for the photon-recoil method of determining the fine structure constant have also been measured. For physical chemistry, the masses of the oxygen isotopes, 17O and 18O have been measured to test the Dunham-Watson formalism for the ro-vibrational energy levels of isotopic variants of a diatomic molecule. By measuring the small shifts in cyclotron frequency due to polarizability, the dipole moments of NH+ and the astrophysically important molecule HCO+ have been measured for the first time. The mass of 19F has also been measured for use as a mass standard. Several improvements and developments to the FSU Precision Penning Trap (FSU-PPT) have enabled these measurements. A vapor loader now allows vapors to be introduced into the trap, greatly increasing the range of species that can be measured. The previously developed technique for measuring a cyclotron frequency ratio, in which two ions are simultaneously trapped, but swapped between large and small cyclotron orbits has been further developed to allow the ion in the large cyclotron orbit to be constantly monitored and therefore recentered more efficiently. This technique has also been extended to enable two-ion cyclotron frequency ratio measurements of non-mass doublets, as well as of multiply charged ions.