  We present studies of proton fluxes in the T10 beamline at CERN. A prototype
high pressure gas time projection chamber (TPC) was exposed to the beam of
protons and other particles, using the 0.8 GeV/c momentum setting in T10, in
order to make cross section measurements of low energy protons in argon. To
explore the energy region comparable to hadrons produced by GeV-scale neutrino
interactions at oscillation experiments, i.e., near 0.1 GeV of kinetic energy,
methods of moderating the T10 beam were employed: the dual technique of
moderating the beam with acrylic blocks and measuring scattered protons off the
beam axis was used to decrease the kinetic energy of incident protons, as well
as change the proton/minimum ionising particle (MIP) composition of the
incident flux. Measurements of the beam properties were made using time of
flight systems upstream and downstream of the TPC. The kinetic energy of
protons reaching the TPC was successfully changed from $\sim0.3$ GeV without
moderator blocks to less than 0.1 GeV with four moderator blocks (40 cm path
length). The flux of both protons and MIPs off the beam axis was increased. The
ratio of protons to MIPs vary as a function of the off-axis angle allowing for
possible optimisation of the detector to select the type of required particles.
Simulation informed by the time of flight measurements show that with four
moderator blocks placed in the beamline, ($5.6 \pm 0.1$) protons with energies
below 0.1 GeV per spill traversed the active TPC region. Measurements of the
beam composition and energy are presented.
