10-9Pa magnitude vacuum partial pressure calibration device and calibration coefficient acquisition method

The invention provides a 0-9Pa magnitude vacuum partial pressure calibration device comprising a fine-adjusting valve, an air source, a sample matching room, eight valves, a sampling room, an auxiliary expansion room, a composite vacuum gauge, a separating vacuum gauge, a small hole, a calibration room, a piston pressure gauge, a sample introducing room and a calibrated partial pressure mass spectrometer. Peripheral equipment is an air exhaust system. An air expansion method is utilized, and higher fore pressure is introduced to the calibration room through air expansion and small hole attenuation so that the lower limit of calibration of the partial pressure mass spectrometer is extended, and calibration of the 10-9Pa magnitude partial pressure mass spectrometer is solved. Besides, the high-precision piston pressure gauge acts as a fore pressure reference standard, and a magnetic suspended rotor vacuum gauge in the prior art is substituted so that uncertainty of measurement is reduced and thus calibration precision is enhanced.