Cosmic-ray isotope measurements with HELIX

Cosmic rays, high energy particles originating from outside of the solar system, are believed to be dominated by particles from our Galaxy at least up to the energy of 10^15 eV. Recent precise measurements of leptons and light nuclei measurements below 1 TeV/nucleon by the satellite experiments PAMELA and AMS-02 are challenging the classical paradigm of Galactic cosmic-ray astrophysics. Understanding the propagation of these particles is essential for studies of the origins of discrepancies with the classical models. Detailed measurements of isotopes with known decay times can provide unique data to constrain the propagation models by revealing the acceleration and the propagation timescales of cosmic rays.
HELIX (High Energy Light Isotope eXperiment) is designed to conduct these measurements for several key isotopes, especially focusing on the clock isotope 10Be measurement up to 10 GeV/n. HELIX consists of a 1 Tesla superconducting magnet with high-resolution tracking system and a ring-imaging Cherenkov detector to make precise measurements of energies more than an order of magnitude higher than currently available. HELIX is scheduled to have a long duration balloon flight out of McMurdo Station during NASA’s 2019 Antarctic balloon campaign. I will describe the current status of the HELIX experiment and discuss what we can learn from the measurements.