Study of the fast calorimeter prototype for modern e⁺e^-factories

Modern factories with high luminosity require fast response of the detector subsystems to suppress severe beam background. The prototype of the electromagnetic calorimeter based on the counter with a pure CsI crystal, novel wavelength shifter with nanostructured organosilicon luminophores and avalanche photodiodes Hamamatsu S8664-55 is discussed. Results of detection of cosmic particle signals by such a prototype are reported.