A method for calibrating a scanner that allows the scan to start quickly. The calculations involve calculation of a composite heat capacity value, MC, from a set of thermodynamic parameters drawn from both the tank system receiving the gas and the station supplying the gas. A control element acting on the brake makes it possible to modify the value of the maximum brake torque and thus to adapt the energy absorber to the mass of the heavy body to maintain an acceleration experienced at a desired value for different masses.