Working properties of GEM-TPC at low pressure

Despite the fact that nuclear technology has already been widely used in the energy sector, the research in this regard have been kept on worldwide. The precise detection of fission fragment tracks is still a knotty issue due to the limits of traditional measurement methods. The inventions of the Gas Electron Multiplier (GEM) as well as its combination with Time Projection Chamber (TPC) detection technology have made many breakthroughs in the multi-parameter correlation measurement of fission fragments tracks. Based on this technology, we designed and built a GEM-TPC detector. To acquire more accurate spatial and energy information, extending the fission fragment tracks by reducing the air pressure in the detector might be an ideal option. At present, since the research on GEM detectors working at low pressure is relatively rare, emphasis in the paper has been put on discussing the working characteristics of our detector in this pressure region in detail. It can be concluded that the lower the working gas pressure, the lower the GEM voltage required to obtain the same gain. In other words, the working voltage range of GEM-TPC will move to a lower level, and the energy resolution of GEM-TPC will first become better and then become worse rapidly as the working gas pressure continues to decrease.