Penning-trap Q-value determination of the Ga71(ν,e-)Ge71 reaction using threshold charge breeding of on-line produced isotopes

We present a first direct Q-value measurement of the Ga71(ν,e-)Ge71 reaction using the TITAN mass-measurement facility at ISAC/TRIUMF. The measurements were performed in a Penning trap on neon-like ⁷¹Ga²¹⁺ and ⁷¹Ge²²⁺ using isobar separation of the on-line produced mother and daughter nuclei through threshold charge breeding in an electron-beam ion trap. In addition, isoionic samples of ⁷¹Ga²¹⁺ and ⁷¹Ge²¹⁺ were stored concurrently in the Penning trap and provided a separate Q-value measurement. Both independent measurements result in a combined Q-value of 233.5 ± 1.2 keV, which is in agreement with the previously accepted Q-value for the ν cross-section calculations. Together with a recent measurement of the ν-response from the excited states in ⁷¹Ge, we conclude that there are no further uncertainties in the nuclear structure, which could remove the persistent discrepancy between the SAGE and GALLEX calibration measurements performed with neutrinos from reactor-produced ⁵¹Cr and ³⁷Ar sources and the theoretical expectation. © 2013 Elsevier B.V.

Duke Scholars

Author Jens Dilling Physics