[en] The strength function for γ-decay to states other than the ground state is described by means of the E1 photoabsorption cross section. Assumption has been made that the γ-ray strength function for excited states has the same Lorentzian shape as for the ground state, but it is shifted upwards, by the excitation energy of low-lying state (Brink hypothesis). The Brink hypothesis has never been verified experimentally. In order to provide such a verification an experiment (a proton capture reaction ⁸⁹Y(p, γ)⁹⁰Zr) was performed using Van de Graaff accelerator in Warsaw. (L.I.)