Electroweak Decay Studies of Highly Charged Radioactive Ions with TITAN at TRIUMF

Abstract

Several modes of electroweak radioactive decay require an interaction between the nucleus and bound electrons within the constituent atom. Thus, the probabilities of the respective decays are not only influenced by the structure of the initial and final states in the nucleus, but can also depend strongly on the atomic charge. Conditions suitable for the partial or complete ionization of these rare isotopes occur naturally in hot, dense astrophysical environments, but can also be artificially generated in the laboratory to selectively block certain radioactive decay modes. Direct experimental studies on such scenarios are extremely difficult due to the laboratory conditions required to generate and store radioactive ions at high charge states. A new electron-beam ion trap (EBIT) decay setup with the TITAN experiment at TRIUMF has successfully demonstrated such techniques for performing spectroscopy on the radioactive decay of highly charged ions.

Studies at the border between nuclear and atomic physics: Weak decays of highly charged ions

“…Therefore, in order to study weak decays of HCIs, it is necessary to create radioactive nuclei in a nuclear reaction, remove a number of bound electrons producing the required atomic charge state, and then preserve this charge state for an extended period of time sufficient for the ions to decay. Apart from the recent studies in the Electron Beam Ion Trap (EBIT) at TRIUMF [17,18], all other investigations of weak decays of HCIs were performed in the experimental storage ring ESR at GSI Helmholtz Center [19].…”

New Test of Modulated Electron Capture Decay of Hydrogen-Like $^{142}$Pm Ions: Precision Measurement of Purely Exponential Decay

“…In addition to the storage ring complex of GSI, such an experiment might be possible at the storage ring CSRe in Lanzhou [108]. Furthermore, experimental studies of weak decays are planned in the Electron Ion Beam Trap of the TITAN facility [109].…”

Weak-Interaction Tests via Precision Superallowed $β$-Decay Studies at TRIUMF

“…The Q EC value is extracted from the mass difference between the parent and daughter nuclear states in the superallowed decay mode, and can be measured to high precision using TRIUMF's Ion Traps for Atomic and Nuclear science (TITAN) [18]. The TI-TAN facility consists of four primary components: (i) A Radio-Frequency Quadrupole (RFQ) linear Paul trap [19,20], (ii) a Multi-Reflection Time-of-Flight (MR-ToF) isobar separator [21], iii) an Electron-Beam Ion Trap (EBIT) for generating Highly Charged Ions (HCIs) [22,23] and performing decay spectroscopy [24][25][26], and (iv) a 3.7 T, high-precision mass Measurement PEnning Trap (MPET) [27]. For experimental studies on RIBs with TITAN, ISAC delivers a continuous beam of ions at 20 keV which are injected into the TITAN-RFQ where they are trapped and cooled using a He buffer gas.…”