Résumé : A hodoscope γ spectrometer comprising 1536 lead-glass cells is described. This detector allows the coordinates and the energies of a large number of gammas (up to ≈ 10) to be measured simultaneously and the masses (with an accuracy of 1%) and the momenta of particles decaying into photons to be determined. The use of fast processors allows selection of events by mass, energy and momentum transfer. The procedure for a fully automatic calibration of the spectrometer in an electron beam (with ∼ 1% accuracy) and for its control during long-term physical experiments is described. © 1986.