Operation and performance of the ASHIPH counters at the KEDR detector

Abstract In 2014 the fully installed ASHIPH (Aerogel, SHifter, PHotomultiplier) system began its operation in the KEDR experiment at the VEPP-4 M e + e − -collider. The system contains 1000 liters of aerogel with refractive index n=1.05 in 160 counters that are arranged in two layers. Cherenkov light collection is preformed by means of wavelength shifters (WLS). 160 Micro-Channel Plate (MCP) PMTs with multialkali photocathode are used as photodetectors. Efficiency of relativistic particles detection was measured with e + e − → e + e − events and cosmic muons. Detection efficiency for under-threshold particles was measured with cosmic muons. From these data π / K -separation of 4 σ at the momentum 1.2 GeV/c was obtained.