High-precision measurement of the mass difference between 102Pd and 102Ru

Abstract The Q -value for the neutrinoless double electron capture on 102 Pd, Q ϵϵ ( 102 Pd), is determined as the atomic mass difference between 102 Pd and 102 Ru. A precise measurement of the Q ϵϵ ( 102 Pd) at the SHIPTRAP Penning trap showed a more than 10 σ deviation to the adopted Atomic Mass Evaluation (AME) value. The reliability of the SHIPTRAP measurement was challenged because the AME value was based on numerous experiments including β and electron capture decays and very precise ( n , γ ) data, all agreeing with each other. To solve the discrepancy, the Q ϵϵ ( 102 Pd) has now been determined with the JYFLTRAP Penning trap at the IGISOL facility in the Accelerator Laboratory of the University of Jyvaskyla. The measurement was performed both with the Time-of-Flight and the Phase-Imaging Ion Cyclotron Resonance techniques. The obtained result, Q ϵϵ ( 102 Pd) = 1203.472(45) keV, is eight times more precise and agrees well with the value obtained at SHIPTRAP, Q ϵϵ ( 102 Pd) = 1203.27(36) keV, confirming that 102 Pd is not a good candidate for a search for neutrinoless double-electron capture.