Fast Calorimeter on the Pure CsI Crystals for the Modern e⁺e⁻ Super Factories

Modern high luminosity e^+e^− factories, like Belle II at SuperKEKB or planned Super Charm-Tau factory require fast calorimeters to cope with severe background conditions. The prototype of the fast electromagnetic calorimeter based on pure CsI scintillation crystals, wavelength shifters with the novel nanostructured organosilicon luminophores, and avalanche photodiodes Hamamatsu S8664-55 is discussed. The results of the tests of the basic element of the calorimeter are reported.