Spallation With Intermediate Energy Protons As Source Of Long-Lived Isomers

A systematic study of spallation reactions with intermediate energy protons and heavy targets was performed to understand the population of long-lived high-spin isomers in the mass region A ≅ 180. Several target materials were considered: natTa, natRe, natW, 186W and natHf. The irradiations were performed at several proton energies in the range 100- 660 MeV. The experimentally determined yields were compared to the calculations performed with the LAHET code. Data and calculations were analyzed to determine the optimal combination of target material and proton beam energy for getting the higher absolute cross-section and the best isomer-to-ground state ratio. (authors)