  We have measured the possible change of the decay rate of 7Be implanted into
hosts of natural beryllium and natural gold. No difference between the 7Be
decay rates in the two hosts is observed within the experimental precision of
0.12%. This result implies that change of the decay rate of 7Be implanted in
different materials cannot be simply expected from the electron affinity
difference consideration lonely and the lattice structure of the host materials
should be taken into account.
