  A new approach is presented to determine the proton-nucleus interactions from
the analysis of the accompanying photon bremsstrahlung. We study the scattering
of $p + ^{208}{\rm Pb}$ at the proton incident energies of 140 and 145~MeV, and
the scattering of $p + ^{12}{\rm C}$, $p + ^{58}{\rm Ni}$, $p + ^{107}{\rm Ag}$
and $p + ^{197}{\rm Au}$ at the proton incident energy of 190~MeV. The model
determines contributions of the coherent emission (formed by an interaction
between the scattering proton and nucleus as a whole without the internal
many-nucleon structure), incoherent emission (formed by interactions between
the scattering proton and nucleus with the internal many-nucleon structure),
and transition between them in dependence on the photon energy. The
radius-parameter of the proton-nucleus potential for these reactions is
extracted from the experimental bremsstrahlung data analysis. We explain the
hump-shaped plateau in the intermediate- and high-energy regions of the spectra
by the essential presence of the incoherent emission, while at low energies the
coherent emission predominates which produces the logarithmic shape spectrum.
We provide our predictions (in absolute scale) for the angular distribution of
the bremsstrahlung photons in order to test our model, results and analysis in
further experiments.
