Data Analysis for the Measurement of High Energy Cosmic Ray Electron/Positron Spectrum with Fermi-LAT

TL;DR

This paper details the measurement of the high-energy cosmic ray electron/positron spectrum from 20 GeV to 1 TeV using Fermi-LAT, emphasizing analysis techniques and spectrum reconstruction methods.

Contribution

It introduces a dedicated analysis method for efficient electron detection and accurate spectrum reconstruction from Fermi-LAT data.

Findings

Measured the electron/positron spectrum from 20 GeV to 1 TeV.

Developed a detailed Monte Carlo simulation for spectrum reconstruction.

Reduced hadron contamination in the measurement.

Abstract

The Large Area Telescope (LAT) instrument on board the Fermi satellite consists of a multi-layer silicon-strip tracker interleaved with tungsten converters (TKR), followed by a CsI crystal hodoscopic calorimeter (CAL). Sixteen TKR and CAL modules are assembled in a 4$\times$4 array. A segmented anticoincidence plastic scintillator (ACD) surrounds the TKRs. The primary cosmic-ray electron/positron energy spectrum has been measured from 20 GeV to 1 TeV using a dedicated event analysis that ensures efficient electron detection and reduced hadron contamination. Results from detailed Monte Carlo simulations have been used to reconstruct the observed energy spectrum to the primary cosmic ray spectrum. We present here details of the analysis procedure and the energy spectrum reconstruction.