Energy Spectrum of Cosmic-ray Electron and Positron from 10 GeV to 3 TeV Observed with the Calorimetric Electron Telescope on the International Space Station

TL;DR

This paper presents the first measurement of the cosmic-ray electron and positron spectrum from 10 GeV to 3 TeV using CALET on the ISS, revealing a power-law spectrum with potential structures above 100 GeV.

Contribution

It provides the first detailed spectrum measurement of cosmic-ray electrons and positrons up to 3 TeV with high precision using the CALET instrument on the ISS.

Findings

Spectrum fits a single power law with index -3.152 ± 0.016.

Potential spectral structures observed above 100 GeV.

Data suggests the need for further analysis with increased statistics.

Abstract

First results of a cosmic-ray electron + positron spectrum, from 10 GeV to 3 TeV, is presented based upon observations with the CALET instrument on the ISS starting in October, 2015. Nearly a half million electron + positron events are included in the analysis. CALET is an all-calorimetric instrument with total vertical thickness of 30 $X_0$ and a fine imaging capability designed to achieve a large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum over 30 GeV can be fit with a single power law with a spectral index of -3.152 $\pm$ 0.016 (stat.+ syst.). Possible structure observed above 100 GeV requires further investigation with increased statistics and refined data analysis.