Design and assembly of BESIII MUON gas monitor

By monitoring the 5.9 keV X-ray of 55Fe radioactive source, we develop a counter to monitor the real-time gas ratio of BESIII MUON detector. After several experiments to study the performance of the counter, we confirmed the finite proportional mode of our monitor, and chose the appropriate high voltage to make the monitor operate permanently and stably. Based on LabVIEW and ROOT, we compile the integrated data acquisition system to display the real time monitor result. According to the signal character, we assemble the high voltage, gas pipe and electronic package board to reduce the cost of system equipments. Finally we report the primary test result after assembly. (authors)