Mainz 2012 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 40: Astroteilchenphysik
HK 40.1: Gruppenbericht
Donnerstag, 22. März 2012, 16:30–17:00, RW 3
A nuclear physics view at the 71Ga(ν,e−)71Ge reaction. — •Annika Lennarz1, Dieter Frekers1, Peter Puppe1, Jan Thies1, and Michael Holl2 — 1Inst. f. Kernphysik, 48149 Münster — 2Inst. f. Theor. Physik, 48149 Münster
In this contribution we will present results from two separate experiments dealing with the neutrino response on 71Ga. Both experiments provide input into the calibration of the SAGE and GALLEX solar neutrino detectors and address a long-standing discrepancy between the measured and evaluated capture rates from the 51Cr and 37Ar neutrino calibration sources. First, we report on a 71Ga(3He,t)71Ge charge-exchange experiment performed at RCNP, Osaka, with the objective to extract with high precision the Gamow-Teller transition strengths to the three lowest-lying states in 71Ge, i.e., the ground state (1/2−), the 175 keV (5/2−) and the 500 keV (3/2−) excited states. These are the states, which are populated via a charged-current reaction induced by neutrinos from terrestrial 51Cr and 37Ar sources. In the second part we present a new precision Q-value measurement for the 71Ga(ν,e−)71Ge reaction using the TITAN mass measurement facility at TRIUMF. From the results of the two experiments we may now conclude that there are no further unknowns in the nuclear structure, which could remove the persistent discrepancy in the SAGE and GALLEX calibration measurement performed with neutrinos from 51Cr and 37Ar sources.