Experiments with Thermalized Rare Isotope Beams from Projectile Fragmentation: A Precision Mass Measurement of the Superallowed $\ensuremath{\beta}$ Emitter $^{38}\mathrm{Ca}$

Experiments with Thermalized Rare Isotope Beams from Projectile Fragmentation: A Precision Mass Measurement of the Superallowed $β$ Emitter ${}^{38}{Ca}$

G. Bollen, D. Davies, M. Facina, J. Huikari, E. Kwan, P. A. Lofy, D. J. Morrissey, A. Prinke, R. Ringle, J. Savory, P. Schury, S. Schwarz, C. Sumithrarachchi, T. Sun, and L. Weissman

Phys. Rev. Lett. 96, 152501 – Published 19 April 2006

Abstract

The mass of the short-lived radio nuclide ${}^{38}{Ca}$ ( $T_{1 / 2} = 440 ms$ ) has been measured with the 9.4-T Penning trap mass spectrometer of the Low-Energy Beam and Ion Trap Facility. A mass uncertainty of $δ m = 280 eV$ has been achieved, corresponding to $δ m / m = 8 \times 10^{- 9}$ . The result makes ${}^{38}{Ca}$ , a superallowed beta emitter, a new candidate to test the conserved-vector-current hypothesis. The experiment is also the first demonstration that short-lived radioactive isotopes produced by projectile fragmentation of relativistic heavy-ion beams can be slowed down and prepared such that precision experiments of this kind are possible.