Cosmic-ray energetics and mass (CREAM) balloon experiment Original Research Article

The Cosmic Ray Energetics And Mass (CREAM) Ultra Long Duration Balloon (ULDB) mission will investigate ultra high energy (1012 to > 5 × 1014 eV) cosmic rays over the elemental range from protons to iron. The measurements will be made with an instrument that consists of a sampling tungsten/scintillator calorimeter preceded by a graphite target with scintillator layers for trigger and track-reconstruction purposes, a transition radiation detector (TRD) for observing heavy nuclei, and a segmented timing-based particle-charge detector. A key feature of the instrument is its ability to obtain simultaneous measurements of the energy and charge of a subset of nuclei by the complementary calorimeter and TRD techniques, thereby allowing in-flight inter-calibration of their energy scales. The energy extent will depend on a series of ULDB flights of identical instruments: three flights will reach 5 × 1014 eV. The different flights can be carried out at essentially any latitude, including the polar regions of either hemisphere. CREAM will be ready for flight one year after the TIGER (Trans-Iron Galactic Element Recorder) ULDB demonstration flight, which is currently scheduled for launch in December 2001.