Helium flux and elemental composition of galactic Cosmic Rays with the DAMPE space mission

Margherita Di Santo,M De Vincenzi,A Capone,A Morselli

doi:10.1051/epjconf/201920901041

Margherita Di Santo, M De Vincenzi + Show 2 more

Open Access

https://doi.org/10.1051/epjconf/201920901041

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Abstract

DAMPE (DArk Matter Particle Explorer) is a space mission project promoted by the Chinese Academy of Sciences (CAS), in collaboration with Universities and Institutes from China, Italy and Switzerland. The detector is collecting data in a stable sun-synchronous orbit lasting 95 minutes at an altitude of about 500 km. It has been launched in December 17th, 2015, from the Jiuquan Satellite Launch Center, in the Gobi Desert. The main goals of the mission are: indirect search for Dark Matter, looking for signatures in the electron and photon spectra with energies up to 10 TeV; analysis of the flux and composition of primary Cosmic Rays with energies up to hundreds of TeV; high energy gamma-ray astronomy. Preliminary results about the Helium flux and Cosmic Ray composition will be presented and discussed.

Highlights

Helium nuclei (He), together with Protons (p), are the most abundant components of Cosmic Rays (CRs)
Choice of a proper PSD energy range to select the charge and so the incoming particles of interest. The use of these event selection criteria is supported by the good agreement between the results of the analysis of flight-data and Monte-Carlo simulations
A preliminary result of the charge spectrum, shown in Fig. 2, has been obtained as the number of events recorded by DAMPE during 17 months as a function of the square root of the arithmetic mean of the two PSD views divided by 1 MeV in order to have a dimensionless number which is, according to the Bethe-Bloch formula, proportional to the charge of the incoming CR nucleus

Summary

Introduction

Helium nuclei (He), together with Protons (p), are the most abundant components of Cosmic Rays (CRs). Several experiments (like AMS [1], CREAM [2], PAMELA [3] and ATIC [4]) found that the measured spectral shape of cosmic He nuclei cannot be well described by a single power law because data exhibit a spectral hardening at energies of hundreds of GeV. This feature of He flux (seen in the p flux) gives rise to different and complex models which try to clarify the origin and the acceleration and diffusion processes of CRs. Here the DAMPE preliminary results about the elemental composition of CRs and the He flux will be presented and discussed

The DAMPE detector

DAMPE data taking and event selection criteria

Preliminary Charge Spectrum and Helium flux with DAMPE

Conclusions