Measurements of He isotopic ratio in cosmic rays in the 100 MeV – 1 GeV range with the PAMELA experiment
26 Oct 2011
1INFN and Dept. of Physics, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133, Rome, Italy
2RIKEN, Advanced Science Institute, Wako 351-0198, Japan
Abstract. The PAMELA satellite-borne experiment was launched on 15 June 2006 from the Baikonur cosmodrome and it has been collecting data since then. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail counter scintillator and a neutron detector. The combination of these devices allows precision studies of the charged cosmic radiation to be conducted over a wide energy range (100 MeV – 1 TeV) with high statistics, with particular focus on the antiparticle component. In this work we present 3He/4He isotopic ratio in the energy range from 100 MeV nucleon−1 to ~1 GeV nucleon−1. The measured abundances are compared with different interstellar/heliospheric propagation calculations which are tuned on previous proton and helium measurements.