Working Properties of Gem-Tpc at Low Pressure

Although nuclear fission has been widely used in the field of energy, its research has never been interrupted. The invention of Gas Electron Multiplier (GEM) and its combination with Time Projection Chamber (TPC) detection technology bring many benefits to the multi-parameter correlation measurement of fission fragments. Due to the short tracks of fission fragments and the randomness of motion directions around the end of the tracks, the precise detection of fission fragments is still very difficult. More accurate position and energy information can be obtained by prolonging the fission fragments tracks with reducing air pressure. Since there are few precedents about GEM detectors under low pressure, this paper aims to find the changing of working performance of the GEM-TPC under different low pressure. The conclusions we obtained are: to get the same gain, the lower the air pressure is, the lower the GEM voltage is required; in other words, GEM-TPC working voltage will move to lower areas, and the energy resolution of GEM-TPC will get better first and then get worse rapidly whit the reducing of gas pressure