Accumulation of the 178m2Hf isomeric nuclei through spallation with intermediate-energy protons of tantalum and rhenium targets

Spallation and fission products in the (p+179Hf) and (p+natHf) reactions

“…Finally, the production cross sections are determined for many radioactive nuclei. In general, the system of data is schematically similar to the results published in [1,2] for Ta to Re targets. The representative spallation peak is strongly manifested for isotopes with mass-numbers near and below the atomic weight of the target material.…”

“…In our previous experiments [1,2] on the spallation of Ta to Re targets, metal samples were irradiated. Even enriched 186 W material was available [2] in a metal form and in enough amount.…”

“…In Refs. [1,2], the yields of high-spin isomers were measured in the spallation of the Ta to Re targets exposed to protons with energy range from 100 to 650 MeV. The enriched 186 W target was indicated as one of the most productive targets for accumulation of the 31-year-lived 178m2 Hf isomeric state located at excitation energy of E i = 2446 keV and at spin I π = 16 + .…”

Production of long-lived hafnium isomers in reactor irradiations

“…The physical cross-sections for high-spin isomer production via spallation of different targets by 600 MeV proton beam have been systematically measured at Dubna, Refs. [21,22]. Definitely, the high yield characterizing spallation reactions was confirmed and quantitatively specified.…”

Induced acceleration of the decay of the 31-yr isomer of 178m2 Hf using bremsstrahlung radiation

“…The uniqueness of the 178m2 Hf isomer has several very essential disadvantages. First, the production of this isomer is an extremely difficult task [13][14][15]. Second, the more productive nuclear reaction is chosen, the longer (in most cases from 6 to 20 years) cooling time for the by-products activity reduction is required.…”