"Here we implement a direct measurement of the Spatial modes distribution carrying Orbital Angular Momentum (OAM) generated in collinear type I SPDC, by using a triggered ICCD camera. Modes up to l = 10 were observed, and the probability amplitude of generation of each mode is reported. We also present a method to observe the topological charge of these modes, which we used for the modes l = 1 and l = 2, proving conservation of OAM."