  Differential cross sections two-body ($\gamma,p$) and ($\gamma,n$) reactions
of the $^4$He nucleus disintegration were measured using the bremsstrahlung
beam of photons at the KIPT linac LEA-300 at the maximum energy ${\rm
E}_{\gamma}^{max}$ = 150 MeV. The reaction products were detected in a
diffusion chamber placed in the magnetic field. The differential cross sections
were measured with a 1 MeV step up to a photon energy of 45 MeV, and with a
greater step at higher energies. The step in the measurements of the polar
angle of nucleon emission was ${10}^{\circ}$ in the c.m.s.
