August, 1998 a sample of 6.3 X 1014 nuclei of
the 4-QP isomer of 178Hf having a half-life of
31 yr and an excitation energy of 2.446 MeV was
irradiated with x-ray pulses from a device typically used
in dental medicine. It was operated at 15 mA and 70 or 90
kV, as selected.
A 2.0 ± 1.3%
increase of emission in the Ground State Band, GSB was
It was the first
demonstration of the excitation of the 178Hf
isomer to a K-mixing level from which it could
subsequently emit the high energy density originally
stored by the isomer.