Energy Calibration of CALET Onboard the International Space Station

Abstract

In August 2015, the CALorimetric Electron Telescope (CALET), designed for long exposure observations of high energy cosmic rays, docked with the International Space Station (ISS) and shortly thereafter began tocollect data. CALET will measure the cosmic ray electron spectrum over the energy range of 1 GeV to 20 TeV with a very high resolution of 2% above 100 GeV, based on a dedicated instrument incorporating an exceptionally thick 30 radiation-length calorimeter with both total absorption and imaging (TASC and IMC) units. Each TASC readout channel must be carefully calibrated over the extremely wide dynamic range of CALET that spans six orders of magnitude in order to obtain a degree of calibration accuracy matching the resolution of energy measurements. These calibrations consist of calculating the conversion factors between ADC units and energy deposits, ensuring linearity over each gain range, and providing a seamless transition between neighboring gain ranges. This paper describes these calibration methods in detail, along with the resulting data and associated accuracies. The results presented in this paper show that a sufficient accuracy was achieved for the calibrations of each channel in order to obtain a suitable resolution over the entire dynamic range of the electron spectrum measurement.

arXiv comment13 pages, 11 figures, published online 4 March 2017

References in corpus (8)

• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• The cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV
• Fermi LAT observations of cosmic-ray electrons from 7 GeV to 1 TeV
• Precise Measurement of Cosmic-Ray Proton and Helium Spectra with the BESS Spectrometer
• The Most Likely Sources of High Energy Cosmic-Ray Electrons in Supernova Remnants
• A New calculation of the atmospheric neutrino flux in a 3-dimensional scheme
• TeV Electron Spectrum for Probing Cosmic-Ray Escape from a Supernova Remnant
• CALET's Sensitivity to Dark Matter Annihilation in the Galactic Halo

Cited by in corpus (26)

• Direct Measurement of the Cosmic-Ray Proton Spectrum from 50 GeV to 10 TeV with the Calorimetric Electron Telescope on the International Space Station
• Extended Measurement of the Cosmic-Ray Electron and Positron Spectrum from 11 GeV to 4.8 TeV with the Calorimetric Electron Telescope on the International Space Station
• 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
• Indications for a high-rigidity break in the cosmic-ray diffusion coefficient
• Observation of Spectral Structures in the Flux of Cosmic-Ray Protons from 50 GeV to 60 TeV with the Calorimetric Electron Telescope on the International Space Station
• Direct Measurement of the Cosmic-Ray Carbon and Oxygen Spectra from 10 GeV$/n$ to 2.2 TeV$/n$ with the Calorimetric Electron Telescope on the International Space Station
• HelMod in the works: from direct observations to the local interstellar spectrum of cosmic-ray electrons
• Measurement of the Iron Spectrum in Cosmic Rays from 10 GeV$/n$ to 2.0 TeV$/n$ with the Calorimetric Electron Telescope on the International Space Station
• Direct Measurement of the Cosmic-Ray Helium Spectrum from 40 GeV to 250 TeV with the Calorimetric Electron Telescope on the International Space Station
• On-orbit Operations and Offline Data Processing of CALET onboard the ISS
• Cosmic-ray Boron Flux Measured from 8.4 GeV$/n$ to 3.8 TeV$/n$ with the Calorimetric Electron Telescope on the International Space Station
• Direct Measurement of the Spectral Structure of Cosmic-Ray Electrons+Positrons in the TeV Region with CALET on the International Space Station
• Search for GeV Gamma-ray Counterparts of Gravitational Wave Events by CALET
• Development of the photo-diode subsystem for the HERD calorimeter double-readout
• Direct Measurement of the Nickel Spectrum in Cosmic Rays in the Energy Range from 8.8 GeV/n to 240 GeV/n with CALET on the International Space Station
• The CALorimetric Electron Telescope (CALET) on the International Space Station: Results from the First Two Years On Orbit
• Selected Topics in Cosmic Ray Physics
• CALET Search for electromagnetic counterparts of gravitational waves during the LIGO/Virgo O3 run
• Charge-Sign Dependent Cosmic-Ray Modulation Observed with the Calorimetric Electron Telescope on the International Space Station
• Measurements of Heavy Cosmic-Ray Nuclei Spectra with CALET on the ISS
• Decaying Fermionic Dark Matter Search with CALET
• Cosmic-Ray Signatures of Dark Matter from a Flavor Dependent Gauge Symmetry Model with Neutrino Mass Mechanism
• Performance assessment of the HERD calorimeter with a photo-diode read-out system for high-energy electron beams
• Tracker-In-Calorimeter (TIC): a calorimetric approach to tracking gamma rays in space experiments
• An Interpretation of the Cosmic Ray $e^{+}+e^{-}$ Spectrum from 10 GeV to 3 TeV Measured by CALET on the ISS
• Precision spectral measurements of Chromium and Titanium from 10 to 250 GeV$/n$ and sub-Iron to Iron ratio with the Calorimetric Electron Telescope on the ISS