Measurement of isomeric yield ratio for the natLu(γ,xn)174m,g Lu reaction measured at 55-, 60-, and 65-MeV Bremsstrahlung energies

In this work, the isomeric yield ratio of ^174m,gLu produced in the ^natLu(γ,xn) reactions with end-point Bremsstrahlung energies of 55-, 60-, and 65-MeV have been determined by using activation and off-line γ-ray spectrometric technique at Pohang Accelerator Laboratory (PAL), Pohang, Korea. The present work is a part of the systematic studies of the isomeric yield ratio in the Pohang Accelerator Laboratory. Studies of isomeric ratios are of considerable importance for both basic nuclear physics research and applications. The isomeric ratio depends on the spin distribution of the compound nuclei, the angular momentum carried away by the emitted particles, the character of the γ-cascade, and the spins of the isomeric states. So far, most experimental results for the isomeric ratios have been measured for the nuclear reactions induced by neutrons, charged particles. The measurements for the nuclear reactions induced by photons are rare and carried out mainly in the energy region of the giant dipole resonance (GDR), from reaction threshold to about 30 MeV, where the detailed information about the reaction mechanism and the multi-pole nature of the photon absorption process is generally not available. During the last few years the essential progress is observable in the development of new and upgrading existing theoretical models for the reactions considered in this energy region. Some new pre-equilibrium models have been developed to define a multi-particle emission and to enhance a quasi-deuteron model. Since the interest of accelerator driven subcritical system (ADSs) is rapidly growing, a photonuclear data will be one of the useful data for the designing of such system.