Eight-channel threshold Cerenkov counter with air radiator

An eight-channel threshold Cerenkov counter with an air radiator is described. The counter is designed for identification of charged particles in the momentum range of 7-22 GeV/c in study of electromagnetic processes with the CASCADE apparatus on the electron (photon) beam of the Serpukhov accelerator. Tests of the counter in the relativistic-electron beam of the synchrotron of the Physics Institute of the Academy of Sciences showed that for a total radiator length of 4.3 m, up to 20 photoelectrons could be emitted from the photocathodes of FEU-49B photomultipliers that had been specially selected on a bench and coated with a spectrum shifter.