TeV--PeV hadronic simulations with DAMPE

Abstract

Cosmic ray research field has entered a brave new world of precise direct measurements in the multi-TeV energy domain thanks to the success of the newest space-borne instruments. DAMPE is a satellite astroparticle detector aimed at probing cosmic ray electrons and gamma rays from few GeV to 10 TeV and cosmic ray nuclei between 10 GeV and few hundred TeV with unprecedented energy resolution. It was successfully launched in December 2015, providing, in particular, the first direct observation of a break in a cosmic ray electron plus positron spectrum around 0.9 TeV. DAMPE presents a unique opportunity of directly measuring the cosmic ray spectrum and composition close to the knee region. However, one of the most challenging limitations on the precision of such measurement arises from the simulation of hadronic interactions in the detector. In spite of the utmost thick and finely segmented calorimeter onboard DAMPE, the cosmic ray proton and nuclei energy measurements still rely significantly on the hadronic Monte Carlo simulation. In this contribution, we discuss the challenges of the hadronic Monte Carlo detector simulation for TeV-PeV particles and review the existing solutions. We also present an in-house software tool which allows connecting the high-energy hadronic event generators, used in CORSIKA and implemented in the CRMC package, to the GEANT4 tool kit. Finally, we discuss preliminary simulation results with DAMPE setup based on this tool. Comparison with the alternative FLUKA simulation is presented as well.

Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission

“…In this analysis, the GEANT4 version 4.10.5 toolkit [20] is used along with the FTFP_BERT physics list * for protons between 10 GeV and 100 TeV and helium nuclei between 10 GeV and 500 TeV. The physics list EPOS-LHC [21] is used for the energy interval 100 TeV -1 PeV for protons and 500 TeV -1 PeV for helium, by linking them to GEANT4 with the Cosmic Ray Monte Carlo (CRMC) package † [22]. Before launching DAMPE into space, several beam tests were performed at CERN, using ion beams of 40 GeV/n, 75 GeV/n and 400 GeV/n [23][24][25].…”

Measurements of the boron-to-carbon and boron-to-oxygen flux ratios in cosmic rays with DAMPE

“…In this work, the GEANT toolkit v4.10.05 [21] with the FTFP_BERT physics list is adopted for the simulations of nuclei. For higher energies we link the EPOS_LHC model by means of a CRMC-GEANT4 interface [22]. The energy response of MC simulations is tuned by including the Birks' quenching [23,24] for the ionization energy deposits in the BGO calorimeter, due to secondary particles with a large charge number and a low kinetic energy.…”

Analysis of cosmic lithium, beryllium and boron with the DAMPE space mission

“…Taking into account the time spent in the SAA along the DAMPE orbit, the instrumental dead-time and the time dedicated to the on-orbit calibration, the total exposure time is 1.44 × 10 8 s corresponding to ∼ 75.85% of the total operation time. Extensive Monte-Carlo (MC) simulations are also performed with the GEANT4 4.10.5 software toolkit adopting the FTFP_BERT and EPOS-LHC physics lists for simulations of the three nuclei in the 10 GeV -500 TeV, linking GEANT4 with the Cosmic Ray Monte Carlo (CRMC) package [5]. The events are initially generated from an isotropic source around the detector, following a E −1.0 spectral shape, and then re-weighted during the analysis to a E −3.0 power-law.…”