Property of LCP-GEM in pure dimethyl ether at low pressure

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 copperclad 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 µm-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 2×10 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.

Cross sections and transport coefficients for electrons in C2H6O and its mixtures with Ar and Ne

“…Because of its insignificant impact on environment and high cetane number (55), it is used as an alternative fuel for diesel engines [2,3]. DME is also used in particle detectors, primarily in Micro Strip Gas Chambers [4][5][6], Gas Electron Multiplier (GEM) detectors [7], as well as in Liquid Cristal Polymer GEM detectors developed by Takeuchu and coworkers [8,9], as an enhanced version of the previous detectors designed for satellite missions. Further advancement of such detectors, breakdown of the fuel mixtures or removal of the molecules potentially emitted into the atmosphere, requires knowledge of reliable electron transport and collisional data.…”