Method to test linearity of quadrupole mass spectrometers by use of a flowmeter and a standard leak

摘要

A linearity test of the quadrupole mass spectrometer signal can be performed by using the pressure generated by the flow rate of a secondary leak as a fix point and varying the flow rate by a primary gas flowmeter around this value. Applying this method, we have investigated three different quadrupole mass spectrometer in a range of helium partial pressures between 10~(-9) Pa and 10~(-4) Pa, corresponding to flow rates of 10~(-7) Pa L s~(-1) to 10~(-2) Pa L s~(-1) in our system. Our preliminary results indicate significant nonlinearities for even modest partial pressure changes.