Cosmic-ray energetics and mass (CREAM) balloon experiment

Abstract

The Cosmic Ray Energetics And Mass (CREAM) Ultra Long Duration Balloon (ULDB) mission will investigate ultra high energy (10 12 to > 5 × 10 14 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 × 10 14 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.