Observation of enhanced activity of the ^178m2Hf isomeric target after its irradiation by bremsstrahlung radiation

Abstract Comparing the spectra acquired during two series of irradiations, the peak intensities of the 178m2 Hf isomer have been found to be higher at the end of each series, while the intensities of the 150 Eu and 133 Ba peaks, which are present in the isomeric target, remain stable. This gives a support to the hypothesis that some additional activity is produced during irradiation. The half-life of this activity appears to be several days.