1. Cosmic Ray Tests of the Prototype TPC for the ILC Experiment
- Author
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Ackermann, K., Arai, S., Arogancia, D. C., Bacala, A. M., Ball, M., Behnke, T., Bito, H., Eckardt, V., Fujii, K., Fusayasu, T., Ghodbane, N., Gooc Jr., H. C., Kijima, T., Hamann, M., Habu, M., Heuer, R. -D., Hiramatsu, K., Ikematsu, K., Kaukher, A., Kuroiwa, H., Janssen, M. E., Kato, Y., Kobayashi, M., Kuhl, T., Lux, T., Matsuda, T., Matsushita, S., Miyazaki, A., Nakamura, K., Nitoh, O., Ohta, H., Reserva, R. L., Sakai, K., Sakamoto, N., Sanuki, T., Settles, R., Sugiyama, A., Takahashi, T., Tomioka, T., Tsuji, H., Watanabe, T., Wienemann, P., Wurth, R., Yamaguchi, H., Yamaguchi, M., Yamaguchi, A., Yamamura, T., Yamaoka, H., Yazu, T., and Yonamine, R.
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Physics - Instrumentation and Detectors ,High Energy Physics - Experiment - Abstract
A time projection chamber (TPC) is a strong candidate for the central tracker of the international linear collider (ILC) experiment and we have been conducting a series of cosmic ray experiments under a magnetic field up to 4 T, using a small prototype TPC with a replaceable readout device: multi-wire proportional chamber (MWPC) or gas electron multiplier (GEM). We first confirmed that the MWPC readout could not be a fall-back option of the ILC-TPC under a strong axial magnetic field of 4 T since its spatial resolution suffered severely from the so called E x B effect in the vicinity of the wire planes. The GEM readout, on the other hand, was found to be virtually free from the E x B effect as had been expected and gave the resolution determined by the transverse diffusion of the drift electrons (diffusion limited). Furthermore, GEMs allow a wider choice of gas mixtures than MWPCs. Among the gases we tried so far a mixture of Ar-CF4-isobutane, in which MWPCs could be prone to discharges, seems promising as the operating gas of the ILC-TPC because of its small diffusion constant especially under a strong magnetic field. We report the measured drift properties of this mixture including the diffusion constant as a function of the electric field and compare them with the predictions of Magboltz. Also presented is the spatial resolution of a GEM-based ILC-TPC estimated from the measurement with the prototype., Comment: 4 pages, 8 figures. Preprint submitted to TIPP09 Proceedings
- Published
- 2009
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