Electromagnetic calorimeters based on CsI crystals

Electromagnetic calorimeters based on cesium iodide crystals are described in two opposite cases. One of them is the largest crystal electromagnetic calorimeter in the world built for the BELLE detector while the other one is the relatively small and thin barrel calorimeter of the CMD-2 detector. Very good possibilities provided by these types of calorimeters for experiments at e+e− colliders are demonstrated.