High Power Proton Accelerator (H.P.P.A.) projects are being proposed in fundamental and applied physics research: radioactive beam production, neutron sources, neutrino factories and transmutation. The front end design of these accelerators is based on a high intensity ion source (several mA up to 100 mA), followed by a Radio Frequency Quadrupole (R.F.Q.) to accelerate protons at several MeV. Finally the beam energy is increased up to 10 MeV or more by a Drift Tube Linac (D.T.L.). Among the parameters needed to be measured for beam control, monitoring and halo formation prevention, the transverse beam profiles are the most difficult to obtain. The large expected specific energy deposition in any interceptive monitor can lead to the destruction of the sensor and in addition to an appreciable amount of radiation production. Therefore traditional multi-wires chambers and wire scanners are not usable under too high duty factor pulsed-beam operation and obviously continuous beam operation. A very attractive phenomenon is the production of visible light by the proton beam-background or additional gas interaction. Transverse beam profiles of the "S.I.L.H.I." E.C.R. proton source (95 keV, 100 mA) have been measured. However, several difficulties emerge to explain the difference shape between the transverse beam profiles deduced from the elementary observation of the emitted light by a C.C.D. camera, a grid profiler (low duty cycle operation) and a residual gas profiler, respectively. More sophisticated measurements using the Doppler effect have been brought into operation to determine the energy and the spatial extension of the different components of the beam (H + ,H 2 + ,H 3 + ).