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

The use of detectors based on plastic scintillator with photomultiplier tubes (PMTs) is common in cosmic-ray experiments to differentiate particle charges. However, in the presence of a calorimeter, the standard method of pulse charge integration over a time longer than a PMT pulse is hampered by abundant albedo particles. The Cosmic Ray Energetics and Mass (CREAM) instrument surmounts this problem by measuring the peak voltage of the PMT pulse within ∼3ns of a threshold crossing in the readout of a timing charge detector (TCD). The design and performance of the TCD is presented. A charge resolution of 0.2e0.2e for oxygen and 0.4e0.4e for iron is obtained for through-going cosmic-ray particles.