Cherenkov electromagnetic calorimeter (ECAL)is being developed to complement the dilepton spectrometer HADES currently operating at SIS18 accelerator (GSI Darmstadt, Germany). Later itwill be used at HADES@FAIR experiments. Neutral meson production in heavy ion collisions and detection of photons from strange resonances in elementary and heavy ion reactionswill be measured with this calorimeter with energy resolution about (5 – 6)%/√(𝐸(𝐺𝑒𝑉))at the beam energy range of 1-10 A GeV. The calorimeter will also improve the electron-hadron separation.
ECALwill cover forward polar angles 16°<Θ< 45° and almost full azimuthal angle of the HADES acceptance and consist of 978 modules divided into 6 sectors. Each module consists of a lead glass Cherenkov counter with light readout by photomultiplier. A dedicated LED based system will be usedto monitor the stability of the calorimeter during beamtime.
Details of ECAL construction and cosmic tests results of ECAL modules in the lab and in-situ at the HADES are discussed.