Abstract In this work, the possibility of different techniques to measure real spectral-angular distributions of radiation under conditions of multiple photon generation is analyzed in dependence of experimental requirements. The technique based on Compton scattering, on narrow collimation of direct gamma-quanta beams, on pair magnetic spectrometer use and on measured opening angles of electron–positron pairs are examined. It is shown that for the measurement of photon spectral-angular distributions and photon multiplicity one can employ the narrow collimation technique. The real photon spectra within the limited emission angle may be measured with a pair magnetic spectrometer. An estimate of the multiplicity of the photons, which are registered by a total absorption spectrometer as one photon and the average energy of these photons may be obtained by measuring the opening angle of the electron–positron pairs generated by the photons in a thin converter.