  A controlled and precise determination of the cross-sections of the fusion
reactions 7Be(p,gamma)8B and 3He(4He,gamma)7Be, which play an important role in
determining the solar neutrino flux, necessitates the knowledge of a precise
value of the electron-capture half-life of 7Be. This half-life may depend on
the material hosting the 7Be atoms via small modifications of the electron
density around the 7Be nucleus. In this brief communication we report on the
measurement of 7Be implanted in four materials: copper, aluminum, sapphire and
PVC. The four results are consistent with a null host dependence within two
standard deviations and their weighted average of 53.236(39)d agrees very well
with the adopted value in the literature, 53.22(6)d. The present results may
exhibit a slight (0.22%) increase of the half-life at room temperature for
metals compared to insulators that requires further studies.
