Trigger System of the NUCLEON Experiment

The NUCLEON experiment is aimed at measuring the spectrum and the elemental composition of cosmic rays (CR) in the 10 11 –10 15 eV energy range. The energy spectrum, the charge, and the mass of CR particles provide additional data on CR sources and the mechanisms of CR acceleration and propagation in the Galaxy. The NUCLEON detector was launched into orbit aboard the Resurs-P No. 2 satellite in December 2014. Statistics in the range up to 5 × 10 14 eV, exceeding the available statistics of the ATIC and CREAM balloon experiments, were obtained in the course of measurements. The NUCLEON experiment relies on modern detectors used in high-energy physics experiments. The design of its trigger system, which is based on plastic scintillator multistrip detectors, is presented. The results of tests conducted at the CERN SPS accelerator are discussed.