CALET for High Energy Electron and Gamma-Ray Measurements on ISS

The CALorimetric Electron Telescope, CALET, mission is proposed for the Japanese Experiment Module Exposed Facility, JEM-EF, of the International Space Station. The mission goal is to reveal the high-energy phenomena in the universe by carrying out a precise measurement of the electrons in the range 1 GeV-10 TeV and the gamma-rays in the range 20 MeV to several TeV. The detector will be composed of an imaging calorimeter of scintillating fibers (IMC) and a total absorption calorimeter of BGO (TASC). The total absorber thickness is 36 r.l for electromagnetic particles and 1.8 m.f.p for protons. The total pay-load weight is nearly 2.5 t and the effective geometrical factor for the electrons ∼1.0 m2sr. The CALET has a unique capability to measure the electrons and gamma-rays above 1 TeV since the hadron rejection power can be 106 and the energy resolution for electromagnetic particles is better than a few % above 100 GeV. Therefore, it is promising to detect any change of the energy spectra and a line signature in the energy distribution, as expected from the dark matter