[en] An attractive concept of phoswitch detector composed of CsI(Tl) and BGO crystals has been developed in our laboratory. This detector combines the phoswitch technique with the intrinsic capabilities of pulse shape discrimination of CsI(Tl). It can detect particles of Z=3 with energies ranging from a few MeV/nucleon up to several hundred MeV/nucleon. The experimental certification of this new concept has been tested at GANIL where high energy light particles produced in the reaction ⁵⁸ Ni + Al (74 MeV/A) were detected at an angle of 15 deg.. The identification matrix Q_slow versus Q_fast makes evident two operation principles of the detector. On the diagonal the particles (γ,p,d,t,^3,4 He) stopped in CsI form a classical identification picture of this crystal. A very good mass based identification was obtained for Z=1 (A=1,2,3), Z=2 (A=3,4) and Z=3 (A=6,7). In the upper part, the particles (p,d,t) stopped in the BGO after passing through CsI are perfectly identified by the additional contribution of the BGO on the axis Q_fast. The proton energies in the reversal point as well as in the detected peak are determined