Abstract: Based on the characteristic that pumping speed of the mechanical pump was constant within a certain pressure range, a new method for testing the linear performance of the leak detector was proposed. Meanwhile, its rationality was also proved through tests. The gas flow in the leak detector was changed by adjusting the inlet pressure of the leak detector. When the helium concentration in mixed gas was constant, the helium gas flow in the leak detector was also changed. So the output of the leak detector was changed. By changing the relationship between the inlet pressure and the output of the leak detector, the linear performance of the leak detector was obtained. The results show that this method is simple, convenient and inexpensive.

Key words: Counterflow, Helium mass spectrometer, Leak testing, Linear, Spacecraft