During electronegative electric field corona discharge

when SF

6

gas goes into sensor

it changes into negative ion by capturing slow electron.The negative ion is compounded into neutral compound by positive ion in air.The output current is reduce because it is taken out of sensor.The decrement of current is proportion to the volume fraction of detected SF

6

gas

which satisfied requirement of detecting the volume fraction of SF

6

gas through converting variable current into the volume fraction of detected SF

6

gas.When the detected SF

6

gas is within（1 200 ppm）

the resolution of sensor is not more than 0.1 ppm

its sensitivity is not less than 1.0 μA/ppm.