Straight-through helium standard leakage hole, 1 *10-3Pam3/s ~ 1 *10-7 Pam3/s large leakage rate standard leak hole. Seepage helium type standard leakage hole is not suitable for large leakage rate standard leakage hole because it will be seriously attenuated.Helium mass spectrometry leak detector using out-of-machine calibration if only -8 or -9 leak holes do not represent the large leakage rate of -4 and 5 is also accurate, Therefore, the external calibration needs to be calibrated at the same time as the standard leakage hole of the large leakage rate and the small leakage rate to ensure that the equipment is normal