The Cosmic Ray Energetics and Mass (CREAM) experiment timing charge detector

The cosmic ray all-particle spectrum has a small steepening of its spectral slope, or 'knee', near 1015 eV. Changes in the nuclear composition of cosmic rays may be associated with the knee and provide clues concerning the origin of the spectral change. An ultra-long duration balloon experiment, Cosmic Ray Energetics and Mass (CREAM), is being constructed to measure cosmic ray elemental spectra at energies just below the knee to look for evidence of changes in composition. CREAM employs a thin calorimeter and transition radiation detector to provide multiple measures of the particle energy. A novel technique, the timing charge detector, is used to identify the charge of the incident primary cosmic ray in the presence of the albedo particles generated by interactions in the calorimeter.