  Cosmic rays represent one of the most important energy transformation
processes of the universe. They bring information about the surrounding
universe, our galaxy, and very probably also the extragalactic space, at least
at the highest observed energies. More than one century after their discovery,
we have no definitive models yet about the origin, acceleration and propagation
processes of the radiation. The main reason is that there are still significant
discrepancies among the results obtained by different experiments, probably due
to some still unknown systematic uncertainties affecting the measurements. In
this paper, we will focus on the detection of galactic cosmic rays in the
10$^{15}$ eV energy range, where the so-called \emph{`knee'} in the
all-particle energy spectrum is observed. The measurement of the (p+He) energy
spectrum is presented and discussed.
