Ultra High Energy Cosmic Rays 2018

Oct 8 – 12, 2018
Ecole Supérieure de Chimie, Paris
Europe/Paris timezone

The Cosmic-Ray Energy Spectrum between 2 PeV and 2 EeV Observed with the TALE detector in monocular mode

Oct 9, 2018, 4:50 PM
20m
Friedel Amphitheater (Ecole Supérieure de Chimie, Paris)

Friedel Amphitheater

Ecole Supérieure de Chimie, Paris

Chimie ParisTech École Nationale Supérieure de Chimie de Paris 11, rue Pierre et Marie Curie 75231 PARIS Cedex 05
ORAL

Charles Jui

Description

We present a measurement of the cosmic ray energy spectrum by the Telescope
Array Low-Energy Extension (TALE) air fluorescence detector (FD). The TALE FD
is also sensitive to the Cherenkov light produced by shower particles. Low
energy cosmic rays, in the PeV energy range, are detectable by TALE as
Cherenkov Events''. Using these events, we measure the energy spectrum from
a low energy of ~2 PeV to an energy greater than 100 PeV. Above 100 PeV TALE
uses the air fluorescence technique to reach energies of a few EeV. In
this talk, we will describe the detector, explain the technique, and present
results from a measurement of the spectrum using ~1080 hours of observation.
The observed spectrum shows a clear steepening near 10^{17.1} eV, along with
an ankle-like structure at 10^{16.2} eV. These features present important
constraints on galactic cosmic rays origin and propagation models. The feature
at 10^{17.1} eV may also mark the end of the galactic cosmic rays flux and the
start of the transition to extra-galactic sources.