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Study of the gamma emission from the 31-yr isomer of 178Hf induced by x-ray irradiation |
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| Authors: | C B Collins F Davanloo M C Iosif R Dussart J M Hicks S A Karamian C A Ur I I Popescu V I Kirischuk J M Pouvesle P McDaniel C E Crist |
| Institution: | (1) Joint Institute for Nuclear Research, Dubna, Moscow oblast, 141980, Russia;(2) Center for Quantum Electronics, University of Texas at Dallas, Richardson, USA;(3) H. Hulubei National Institute of Physics and Nuclear Engineering and IGE Foundation, Bucharest, Romania;(4) Institute for Nuclear Research, National Academy of Sciences of Ukraine, pr. Nauki 47, UA-252028 Kiev, Ukraine;(5) GREMI, CNRS-Universite d'Orleans, France;(6) Air Force Research Laboratory, DEPA, Kirtland Air Force Base, Albuquerque, New Mexico, USA;(7) Sandia National Laboratory, Albuquerque, New Mexico, USA |
| Abstract: | A sample containing 6.3×1014 nuclei of the 16+ 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 operated at 15 mA to produce bremsstrahlung with an endpoint energy of 90 keV. The gamma spectra of the isomeric target were taken with a Ge detector. The intensity of the 325.5-keV (6+ → 4+) transition in the ground-state band of 178Hf was found to increase by about 2%. Such an enhanced decay of the 178Hf isomer is consistent with an integrated cross section value of 3×10?23 cm2 keV if resonance absorption occurs within energy ranges corresponding to the maxima of the x-ray flux, either near 20 keV or at the energies of the characteristic emission lines of W. |
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