Cross sections and thermonuclear reaction rates for¹⁸¹Ta(alpha,n)¹⁸⁴Re,¹⁶⁹Tm(alpha,n)¹⁷²Lu,¹⁹¹Ir(alpha,n)¹⁹⁴Au and¹⁹⁷Au(alpha,n)²⁰⁰Tl

Abstract

Cross sections for the 181 Ta(α, n) 184 Re reaction, populating the 3 − ground state, were measured for energies ranging from 13 to 28 MeV by measuring the radioactive products. These and previous results, for mass numbers ranging from 160 to 200, are compared with theoretical cross sections using transmission coefficients obtained from new prescriptions of optical model parameters for this mass region. Calculations were performed with the 'STAPRE' code using a statistical model including pre-equilibrium emission. Thermonuclear reaction rates for explosive stellar nucleosynthesis temperatures were calculated from our experimental values as well as from other experimental data for 169 Tm(α, n) 172 Lu, 191 Ir(α, n) 194 Au and 197 Au(α, n) 200 Tl reactions.