Charge-Sharing and Electron-Transfer Characteristics of a Gas Electron Multiplier (GEM)

The charge sharing and electron-transfer process of a gas electron multiplier (GEM) with a high density of holes (60 m in diameter at 100 m of pitch) were examined. The GEM operated at a lower applied voltage due to the smaller size of the GEM holes; thus, a higher electric eld is seen in the multiplication channels. The electron collection eciency and the charge sharing were found to depend on the external elds, as well as on the GEM voltage. The electron collection eciency approached 90 % with a full collection of primary electrons under optimized GEM eld conditions, and the range of the drift eld for ecient electron collection to reach a plateau increased with the GEM voltage. The positive-ion feedback is also estimated. KCI Citation Count: 6