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

摘要

The Q-value for the neutrinoless double electron capture on Pd-102, Q(epsilon epsilon)(Pd-102), is determined as the atomic mass difference between Pd-102 and Ru-102. A precise measurement of the Q(epsilon epsilon) ((102)pd) at the SHIPTRAP Penning trap showed a more than 10 sigma 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 beta and electron capture decays and very precise (n, gamma) data, all agreeing with each other. To solve the discrepancy, the Q(epsilon epsilon)((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(epsilon epsilon)((10)(2)pd)= 1203.472(45) keV, is eight times more precise and agrees well with the value obtained at SHIPTRAP, Q(epsilon epsilon)((102)pd)= 1203.27(36) keV, confirming that Pd-102 is not a good candidate for a search for neutrinoless double-electron capture. (C) 2018 Elsevier B.V. All rights reserved.