Stopped, bunched beams for the TwinSol facility

A. A. Valverde*, M. Brodeur, D. P. Burdette, J. A. Clark, J. W. Klimes, D. Lascar, P. D. O’Malley, R. Ringle, G. Savard, V. Varentsov

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Tests of the unitarity of the Cabbibo-Kobayashi-Masakawa (CKM) matrix offer an important avenue for constraining the Standard Model of the electroweak interaction. Several methods are currently used to determine V ud , the largest element in the top-row normalization test. One such method is through the study of superallowed T = 1/2 mixed mirror transitions, which offers a complementary method to the current most-precise value that is determined from superallowed pure Fermi 0 + → 0 + transitions. The precision currently achievable by this method is currently limited by the very low number of transitions for which the Fermi-to-Gamow-Teller mixing ratio ρ has been measured. St. Benedict, the Superallowed Transition Beta-Neutrino Decay-Ion-Coincidence Trap, is currently under development at the University of Notre Dame’s Nuclear Science Laboratory, and intends to determine ρ for a range of new isotopes through measurements of the β-neutrino asymmetry parameter a βν using a linear Paul trap. In order to trap these ions, the fast, continuous secondary beam separated by the TwinSol twin solenoid separator must be thermalized and bunched. The system through which this will be done will feature a large-volume gas cell in which the ions will be thermalized, a double-RF-funnel-based ion guide system for the extraction of the ions, and a radiofrequency quadrupole (RFQ) to provide cooled ion bunches for capture in the Paul trap.

Original languageEnglish (US)
Article number38
JournalHyperfine Interactions
Issue number1
StatePublished - Jun 1 2019


  • Beam cooling
  • Fundamental symmetries
  • Ion trapping
  • Mirror transitions
  • RFQ
  • Radioactive ion beams

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Nuclear and High Energy Physics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


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