The CALorimetric Electron Telescope (CALET) Status and Initial Results

Abstract

The CALET space experiment, that was developed by collaborators in Japan, Italy and the United States, has been mounted as an attached payload on the International Space Station (ISS) Japanese Experiment Module – Exposed Facility (JEM-EF) since August 2015. Over the >1,000 days of data taking the instrument has accumulated more than ~630 million triggered events > 10 GeV with a live time fraction of 84%. These data have been used to study electrons to ~5 TeV, gamma rays above 10 GeV and nuclei with Z=1 to 40 up to 1,000 TeV. Multiple peer-reviewed journal publications detailing the CALET results are now available. The instrument consists of a particle charge identification module, a thin imaging calorimeter (3 r.l. in total) with tungsten plates interleaving scintillating fiber planes, and a thick calorimeter (27 r.l.) composed of lead tungstate logs. CALET has the depth, imaging capabilities and energy resolution for excellent separation between hadrons, electrons and gamma rays. This presentation summarizes the instrument design, on-orbit performance, and provides highlights of the most important CALET results over the last three years.