Colloquium: John Krizmanic, March 9, 2017

Date: March 9
Speaker: John Krizmanic (NASA/GSFC)
Title: The CALorimetric Electron Telescope (CALET) on the International Space Station: Results from the First Year of Operation
Abstract: CALET is an experiment, developed by a Japanese-Italian-US collaboration, that was launched from Tanegashima Space Center aboard the HTV-5 Transport Module on August 19, 2015 and was attached to Port 9 of the JEM-EF on the ISS on August 25th. After an extended check-out period, CALET science operations began in October 2015, starting its 5 year mission. CALET is designed to measure the fluxes of electrons+positrons from 1 GeV to 20 TeV, gamma rays above 1 GeV to potentially 10 TeV, and nuclei (Z=1 to 40) from 10 GeV to 1000 TeV. These measurements support CALET's scientific goals to investigate the mechanism of cosmic-ray acceleration and propagation in the Galaxy, to search for nearby astrophysical sources of high-energy electrons, and to search for signatures of dark matter. The main CALET instrument (CAL) is comprised of three modules: 1) two layers of segmented plastic scintillators for cosmic-ray charge identification (CHD), 2) a 3 X0-thick tungsten plate/scintillating fiber imaging calorimeter (IMC), and 3) and a 27 X0-thick, segmented lead-tungstate calorimeter (TASC). The IMC and TASC provide measurements of the longitudinal and lateral shower development, yielding excellent electron/hadron/gamma-ray separation through CALET's energy range. CALET also includes a dedicated Gamma-ray Burst Monitor (CGBM) instrument that monitors the sky in two energy bands, 7 keV - 1 MeV and 40 keV-20 MeV, using two different types of scintillator detectors. As of February 24 2017, the CGBM has measured light curves from 50 GRBs. In this talk, I will present the scientific motivation for the CALET mission, describe the instrument configuration and performance in terms of CALET's cosmic radiation measurement capability, and report results from the first year of operation, including upper limits on X-ray and Gamma-ray counterparts to GW 151226.