Survey of the response of standard limited streamer tubes over the complete range of three-component gas mixtures of isobutane, CO2, Argon

We present the results of a systematic study of three-component gas mixtures containing argon, isobutane, and carbon dioxide. The study used production-type chambers from the SLD Warm Iron Calorimeter (WIC), instrumented with standard plastic streamer tubes, and triggered by cosmic-ray muons. Pulse height spectra are presented as a function of high voltage, over a wide range of mixtures of these three gases. Various features and similarities observed throughout this three-dimensional mixture space are important clues to an understanding of the underlying physics of discharge mechanisms in wire detectors.