The influence of oxygen contamination on the performance of a mini-jet-cell-type drift chamber for the JLC-CDC
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- 作者：Kuroiwa ; H. ; Nitoh ; O. ; Fujii ; K. ; Khalatyan ; N. ; Kobayashi ; M. ; Asano ; Y. ; Bacala ; A. ; Hoshina ; K. ; et. al.
- 关键词：29.40.G ; Drift chamber ; Oxygen contamination ; Electron attachment ; Cool gas ; JLC
- 刊名：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
- 出版年：2004
- 出版时间：January 11, 2004
- 年：2004
- 卷：516
- 期：2-3
- 页码：377-389
- 全文大小：757 K
文摘
We have studied, using cosmic rays, the influence of oxygen contamination on the performance of a test drift chamber filled with a CO<sub>2sub>:iso-C<sub>4sub>H<sub>10sub> (90:10) gas mixture. The test chamber has the same mini-jet-cell structure as our proposed central tracker for JLC (JLC-CDC). We observed significant deterioration of its spatial resolution with oxygen contamination in the long drift region, though the wire efficiency stayed essentially 100 % up to 50ppm of oxygen over the full drift length of 5cm. From the drift-time dependence of signal charge, we evaluated the electron attachment rates at different oxygen concentrations. The results were found to be consistent with a proposed empirical expression for the attachment of thermal electrons.