Journal article Open Access
Ahmad, I.; Mashayekhi, A.; Banar, J. C.; McNabb, D. P.; Becker, J. A.; Miller, G. G.; Gemmell, D. S.; Moore, E. F.; Kraemer, A.; Pangault, L. N.; Rundberg, R. S.; Schiffer, J. P.; Shastri, S. D.; Wang, T. F.; Ja, Becker; Wilhelmy, J. B.
Enhanced decay of the 31-yr isomer of 178Hf induced by x-ray irradiation has been reported previously. Here we describe an attempt to reproduce this result with an intense "white" x-ray beam from the Advanced Photon Source. No induced decay was observed. The upper limits for the energy-integrated cross sections for such a process, over the range of energies of 20–60 keV x rays, are less than 2×10^-27cm^2 keV, below the previously reported values by more than 5 orders of magnitude; at 8 keV the limit is 5×10^-26 cm^2 keV.