Source on the 197Hg basis for Moessbauer investigations

The possibility of using a γ-quanta source based on 197 Hg in Moessbauer experiments was investigated. The source was made of Pd amalgam. A mixture of a 105Pd powder with the appropriate amount of Hg of natural isotopic composition was annealed at 400 deg C for 2 hr and at 200 deg C for 100 hr. At the liquid helium temperature, the Moessbauer spectrum of Au was measured with the aid of a Pd-Hg source (11.5% Hg). A NaI(Tl) crystal of thickness 2 mm was used as a γ-ray detector. From the analysis of the data obtained it was established that the width of the emission line for all the three sources conicides with the natural width, which corresponds to the half-life of the excited level tausub(1/2)=(1.89+-0.03) nsec