What factors affect the detection accuracy of helium mass spectrometry leak detector?

In various detection processes, the detection accuracy of helium mass spectrometer leak detector should be controlled. So, what are the factors that affect the detection accuracy of helium mass spectrometry leak detector? Let's take a look today.

1.Detecting Pressure

For different measurement conditions, the leakage rate depends on the test pressure differently. In general, when the porosity is high, the detection pressure has a greater impact on the leakage rate, while the influence on the porosity is low. In addition, as the detection pressure increases, it also brings a series of problems, such as the effect of temperature and the required stabilization time. Therefore, it is recommended to perform leak detection on a specific workpiece within a certain pressure range, and then select a lower pressure to meet the test requirements to determine the final test pressure.

2.Detection volume

In a particular leakage rate value, if the detection volume increases, the corresponding pressure drop rate is lower, so the measurement time needs to be increased accordingly. Under certain conditions, if the measurement volume is not minimized, the required accuracy and sensitivity of the measurement may not be achieved.

3.Stabilization time

When inflated, the compressed air enters a closed container, causing a series of thermodynamic-dynamic changes. That is, when a certain volume of compressed air is quickly moved to a closed container, the pressure is reduced. If the measurement is made at this time, this pressure change will be treated as a pressure change caused by the leak, which will affect the accuracy of the measurement results. The "punching effect" is affected by the inflation pressure, test volume, and test material. As the inflation pressure or test volume increases, the pressure drop caused by inflation becomes apparent. One way to solve this problem is to add a stable time between inflation and measurement to eliminate this effect.

4.Temperature

For a gas in a closed container, when the temperature increases, its internal pressure also increases. Therefore, temperature changes inevitably become an important factor affecting pressure changes.