[en] The authors present an element of a measurement device aimed at measuring masses of fission fragments by simultaneously determining the energy and velocity of each particle. This element more particularly concerns the operation of start-stop detectors, and is in relationship with the time-of-flight measurement. It is a notably simple time-amplitude converter. After a presentation of start-stop detectors, of their principles, operation, interests and benefits, the author presents the developed circuit, describes its operation, and reports its performance assessment in terms of resolution and linearity. The next part reports an experimental study of the whole apparatus: signal shape and resolution