Spallation and fission products in the (p Hf-179) and (p Hf-nat) reactions

作者：Karamian S A; Ur C A^*; Adam J; Kalinnikov V G; Lebedev N A; Vostokin G K; Collins C B; Popescu I I

来源：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment , 2009, 600(2): 488-497.

DOI：10.1016/j.nima.2008.12.001

• Protons
• Spallation
• Target activation
• Cross-sections
• High-spin isomers
• Fission-to-spallation ratio

Production of Hf and Lu high-spin isomers has been experimentally studied in spallation reactions induced by intermediate energy protons. Targets of enriched Hf-179 (91%) and Hf-nat were bombarded with protons of energy in the range from 90 to 650 MeV provided by the internal beam of the Dubna Phasotron synchrocyclotron. The activation yields of the reaction products were measured by using the gamma-ray spectroscopy and radiochemistry methods. The production cross-sections obtained for the Hf-179m2, Hf-178m2 and Lu-177m isomers are similar to the previously measured values from the spallation of Ta, Re and W targets. Therefore, the reactions involving emission of only a few nucleons, like (p,p'), (p,p'n) and (p,2pn), can transfer high enough angular momentum to the final residual nuclei with reasonable large cross-sections. A significant gain in the isomeric yields was obtained when enriched 179Hf targets were used. The mass distribution of the residual nuclei was measured over a wide range of masses and the fission-to-spaliation ratio could be deduced as a function of the projectile energy. Features of the reaction mechanism are briefly discussed.

• 出版日期2009-3-1