Search for Oscillation of the Electron-Capture Decay Probability of \(^{142}\)Pm

• Published in: arXiv.org 2008-07
• Main Authors: Vetter, P A, Clark, R M, Dvorak, J, Freedman, S J, Gregorich, K E, Jeppesen, H B, Mittelberger, D, Wiedeking, M
• Format: Article
• Language: English
• Subjects: Alpha rays; Beta decay; Bombardment; Cyclotrons; Electron capture; Electrons; Implantation; Modulation; Separators; X-rays
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0807.0649

We have searched for time modulation of the electron capture decay probability of \(^{142}\)Pm in an attempt to confirm a recent claim from a group at the Gesellschaft f\"{u}r Schwerionenforschung (GSI). We produced \(^{142}\)Pm via the \(^{124}\)Sn(\(^{23}\)Na, 5n)\(^{142}\)Pm reaction at the Berkeley 88-Inch Cyclotron with a bombardment time short compared to the reported modulation period. Isotope selection by the Berkeley Gas-filled Separator is followed by implantation and a long period of monitoring the \(^{142}\)Nd K\(_{\alpha}\) x-rays from the daughter. The decay time spectrum of the x-rays is well-described by a simple exponential and the measured half-life of 40.68(53) seconds is consistent with the accepted value. We observed no oscillatory modulation at the proposed frequency at a level 31 times smaller than that reported by Litvinov {\it et al.} (Phys. Lett. B 664 (2008) 162; arXiv:0801.2079 [nucl-ex]). A literature search for previous experiments that might have been sensitive to the reported modulation uncovered another example in \(^{142}\)Eu electron-capture decay. A reanalysis of the published data shows no oscillatory behavior.