Résumé : Small Angle Detector (SAD-150) is a PbWO4 heavy crystal electromagnetic calorimeter with high energy and coordinate resolution for multiphoton events. It has been included in the GAMS-4π setup and calibrated in muon and electron beams. Test measurements of forward emitted π0 and η in the π- p charge exchange reactions with 32.5 GeV/c π- at the IHEP proton synchrotron are reported. The measured mass resolution in the η region agrees with the design value SAD-150 performance does not deteriorate with π- intensities up to 106 π-/s per cell.