Measurement of Cosmic-Ray Nuclei with the Third Flight of the CREAM Balloon-Borne Experiment

International audienceThe balloon-borne Cosmic Ray Energetics And Mass experiment had its third flight (CREAM-III) over Antarctica for 29 days from December 17, 2007 to January 19, 2008. CREAM-III was designed to directly measure the elemental spectra of cosmic-ray nuclei from Hydrogen to Iron in the energy range from 10^12 to 10^15 eV. Energy of incident cosmic rays was measured with a calorimeter that consisted of a densified carbon target directly above a stack of 20 alternating layers of tungsten and scintillating fiber ribbons. Multiple charge measurements were independently made with the silicon charge detector (SCD), Cherenkov Camera (CherCam), and a Timing Charge Detector (TCD) in order to identify particles and minimize backscattering effects from the calorimeter. Compared to previous CREAM flights, the electronic noise of CREAM-III was reduced, significantly lowering the energy threshold. Results from on-going analysis of the energy spectra will be presented

Boron And Carbon Cosmic rays in the Upper Stratosphere (BACCUS)

International audienceThe balloon-borne BACCUS experiment measures directly the elemental spectra of cosmic-ray nuclei from protons to Fe over the energy range ~10^12 to 10^15 eV. It focuses on the energy dependence of secondary to primary ratios (e.g. B/C) to investigate cosmic-ray propagation history. BACCUS consists of redundant and complementary particle detectors including the Timing Charge Detector (TCD), Transition Radiation Detector (TRD), Cherenkov Detector (CD), Silicon Charge Detector (SCD), and Calorimeter (CAL). The TCD measures the light yield produced by the particle in plastic scintillator. The TRD provides energy measurements of incident 3 ≤ Z ≤ 26 nuclei in the 102 – 105 Lorentz factor range. The CD responds only to particles with velocity exceeding the velocity of light in the plastic. It allows BACCUS to reject the abundant low energy cosmic rays present in the polar region. The CAL is used to determine the particle’s energy for all nuclei for 1 ≤ Z ≤ 26. With the SCD based on pixellation, in addition to the TCD based on timing, and the CD, the BACCUS instrument implements virtually all possible techniques to minimize the effect of backscatter on charge measurements in the presence of a large particle shower in the CAL. The 30 day flight was carried out successfully over Antarctica in 2016 from Nov. 28 to Dec. 28. The integration test, and performance of instruments will be presented