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Abstract: The CALorimetric Electron Telescope (CALET) is an imaging calorimeter under construction for launch to the ISS in 2014 for a planned 5year mission. CALET consists of a charge detection module (CHD) with two segmented planes of 1cm thick plastic scintillator, an imaging calorimeter (IMC) with a total of 3 radiation lengths ( ) of tungsten plates read out with 8 planes of interleaved scintillating fibers, and a total absorption calorimeter (TASC) with 27 of lead tungstate (PWO) logs. The primary objectives of the instrument are to measure electron energy spectra from 1GeV to 20TeV, to detect gamma-rays above 10GeV, and to measure the energy spectra of nuclei from protons through iron up to 1,000TeV. In this paper we describe how the geomagnetic field at the 51.6° inclination orbit of the ISS can be used to allow CALET to measure the rare ultra-heavy (UH) cosmic ray (CR) abundances, which provide important clues for the CR source and acceleration mechanism. The CHD scintillator response is relatively insensitive to energy above minimum ionization, and the angle-dependent rigidity as a function of geomagnetic latitude can be exploited to discriminate particles above this energy threshold. Such events require corrections for trajectory in instrument that can be made with only the top 4 layers of the IMC, which allows for considerably greater geometric acceptance than for events that require passage through the TASC for energy determination. Using this approach CALET will be able to measure UH CR relative abundances over its expected mission with superior statistics to previous space instruments. [Copyright &y& Elsevier]

Abstract: The CALorimetric Electron Telescope (CALET) is an imaging calorimeter under construction for launch to the ISS in 2014 for a planned 5year mission. CALET consists of a charge detection module (CHD) with two segmented planes of 1cm thick plastic scintillator, an imaging calorimeter (IMC) with a total of 3 radiation lengths ( ) of tungsten plates read out with 8 planes of interleaved scintillating fibers, and a total absorption calorimeter (TASC) with 27 of lead tungstate (PWO) logs. The primary objectives of the experiment are to measure the electron energy spectra from 1GeV to 20TeV, to detect gamma-rays above 10GeV, and to measure the energy spectra of nuclei from protons through iron up to 1000TeV. In this paper we describe how the geomagnetic field at the 51.6 inclination orbit of the ISS can be used to allow CALET to measure the distinct electron and positron fluxes. The positron fraction has been seen to rise above GeV by previous experiments (HEAT, AMS-01), and more recently to continue to increase to higher energies ( GeV for PAMELA, GeV for Fermi and GeV with the best statistics for AMS-02). Utilizing the geomagnetic cutoff, CALET will be able to distinguish electrons and positrons in the –20GeV energy range where the positron fraction turns upward to complement existing high statistics measurements. [Copyright &y& Elsevier]