Property of LCP-GEM in Pure Dimethyl Ether at Low Pressure

Y. Takeuchi; T. Tamagawa; T. Kitaguchi; S. Yamada; W. Iwakiri; F. Asami; A. Yoshikawa; K. Kaneko; T. Enoto; A. Hayato; T. Kohmura; the GEMS/XACT team

doi:10.1088/1748-0221/9/01/c01002

arXiv · 1312.2343

Property of LCP-GEM in Pure Dimethyl Ether at Low Pressure

Y. Takeuchi·T. Tamagawa·T. Kitaguchi·S. Yamada·W. Iwakiri·F. Asami·A. Yoshikawa·K. Kaneko·T. Enoto·A. Hayato·T. Kohmura·the GEMS/XACT team

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Abstract

We present a systematic investigation of the gain properties of a gas electron multiplier (GEM) foil in pure dimethyl ether (DME) at low pressures. The GEM is made from copper- clad liquid crystal polymer insulator (LCP-GEM) designed for space use, and is applied to a time projection chamber filled with low-pressure DME gas to observe the linear polarization of cosmic X-rays. We have measured gains of a 100 um-thick LCP-GEM as a function of the voltage between GEM electrodes at various gas pressures ranging from 10 to 190 Torr with 6.4 keV X-rays. The highest gain at 190 Torr is about 2x10^4, while that at 20 Torr is about 500. We find that the pressure and electric-field dependence of the GEM gain is described by the first Townsend coefficient. The energy scale from 4.5 to 8.0 keV is linear with non-linearity of less than 1.4% above 30 Torr.

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Y. Takeuchi, T. Tamagawa, T. Kitaguchi, S. Yamada, W. Iwakiri, F. Asami, A. Yoshikawa, K. Kaneko, T. Enoto, A. Hayato, T. Kohmura, the GEMS/XACT team. 2014-05-27. Property of LCP-GEM in Pure Dimethyl Ether at Low Pressure. https://doi.org/10.1088/1748-0221/9/01/c01002

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