Cosmic ray tests of a GEM-based TPC prototype operated in Ar-CF4-isobutane gas mixtures
arXiv:1008.5068 · doi:10.1016/j.nima.2011.02.042
Abstract
Argon with an admixture of CF4 is expected to be a good candidate for the gas mixture to be used for a time projection chamber (TPC) in the future linear collider experiment because of its small transverse diffusion of drift electrons especially under a strong magnetic field. In order to confirm the superiority of this gas mixture over conventional TPC gases we carried out cosmic ray tests using a GEM-based TPC operated mostly in Ar-CF4-isobutane mixtures under 0 - 1 T axial magnetic fields. The measured gas properties such as gas gain and transverse diffusion constant as well as the observed spatial resolution are presented.
A supplemental material (Addendum to be published in Nucl. Instrum. Methods Phys. Res. A) was added at the end of the manuscript to help readers understand the formulas in Appendix B. No changes in the conclusion. 24 pages, including 21 figures