Perturbation of the decay rate of^90mNb by implantation in metals

The perturbation of the decay constant of90mNb implanted in various transition metals (Zr, Nb, Hf, Ta, Ag and Au) has been determined by direct half-life measurements. Particular care was taken to evaluate and minimize possible systematic errors. The maximum relative change found is ?Au-?Nb/?Nb=(4.5±0.8)%