The calorimetric electron telescope (CALET) for high-energy astroparticle physics on the international space station

During a five year mission the CALET space experiment, currently under development by collaborators in Japan, Italy and the United States, will measure the flux of Cosmic Ray electrons (and positrons) from 1 GeV to 20 TeV, gamma rays from 10 GeV to 10 TeV and nuclei with Z=1 to 40 from 10 GeV to 1,000 TeV. These measurements are essential to investigate possible nearby astrophysical sources of high-energy electrons, study the details of galactic particle propagation and search for dark matter siya.tures. The instrument consists of a module to identify the particle charge, a thin imaging calorimeter (3 radiation lengths) with tungsten plates interleaving scintillating fiber planes, and a thick calorimeter (27 radiation lengths) composed of lead ttmgstate logs. CALET has the depth, imaging capabilities and energy resolution necessary for excellent separation between hadrons, electrons and gamma rays. The instrument is currently being prepared for launch, during the 2014 time frame, to the International Space Station (ISS) for installation on the Japanese Experiment Module Exposed Facility (JEM-EF). This paper summarizes the instrument design and performance.