Application of low energy photon spectroscopy in isomer production of Hf, W, Ir, Pt, Au and Hg using (γ, γ′) reactions

Abstract

In the present work we present results of activation analysis of various heavy metals using bremsstrahlung gammas to create short lived nuclear isomers. The method uses inelastic gamma scattering on natural samples of Hf, W, Ir, Pt, Au, and Hg to produce the isomers 179mHf, 183mW, 191mIr, 195mPt, 197mAu, and 199mHg. For isomer detection, a comparison is made between the minimum detection limit achievable using either isomeric gammas or the characteristic X-rays which follow internal conversion. This latter mechanism has the bulk of the decay probability for most of the nuclei studied. An election linac was used to produce the bremsstrahlung, with electron energies between 6 and 8 MeV being optimal. Interferences were investigated and optimal irradiation and counting times were determined using predominantly low energy photon spectroscopy. A linear electron accelerator producing bremsstrahlung radiation with a maximum quanta of 6–8 MeV has proven to be optimal for the isomeric excitation.