The CALET mission on International Space Station

The CALorimetric Electron Telescope (CALET) mission is proposed for the observation of various components of cosmic-rays as well as gamma-rays on the Exposure Facility of the, Japanese Experiment Module ( EF/JEM) on the International Space Station (ISS). The detector is composed of an imaging calorimeter of scintillating fibers (IMC), a total absorption calorimeter of BGO (TASQ and a silicon pad module at the top of IMC. The total thickness of absorber is 36 r.1 for the electromagnetic particles and 1.8 m.f.p for protons. The total weight of the payload, including the detector, the support, the interface instruments with JEM so on, is nearly 2,500 kg and the geometrical factor for the electrons is about 1 m(2) sr. The CALET has a unique capability to measure electrons and gamma-rays beyond 1 TeV since the hadron rejection power is 10(6). The energy resolution for the electro-magnetic particles is better than a few % above 100 GeV. The detector is optimally designed to detect changes in the energy spectra caused by physical processes, or a line signature in the energy distribution expected from annihilations of dark matter candidates. This paper is the first presentation by the international team of the CALET collaboration.