First results of primary cosmic ray spectrum measurements using balloon-borne detector SPHERE

Results of the first winter 1998 measurements of the cosmic ray energy spectrum above 10 eV with SPHERE detector are presented. Detector was lifted by fastened balloon above snow field to 1 km altitude. Cherenkov light of the air showers reflected from the snow was detected. Detector consists of the 1.2 m diameter spherical mirror and the mosaic of 19 photomultipliers.