The type of helium leak detector used depends a lot on the application. If system vacuum pumps are to be used, then the leak detector is not expected to pump the system down to vacuum levels. Thus the type of leak detector used would be one with a small roughing or backing pump. If the system pumps cannot be shutdown, allowances must be calculated since all the helium is not coming through the helium leak detector. Some helium flow is going through the system vacuum pumps. This is called a split flow.

Helium leak detectors with larger pumps are good if the system pumps are not available or if it is a new tool before pumps are installed. These leak detectors have larger pump systems to enable the leak detector to pump the system down to an acceptable level.

In each leak detector specifications, there is a vacuum level in which must be achieved before the helium leak detector will introduce flow to the ion source to enable a reading.

Leak detectors are classified as wet or dry. This refers to whether there is oil in the pumping system. Many applications require dry or oil-free pumping systems due to oil contamination coming from the leak detector entering the vacuum system. Dry leak detectors are usually more expensive that wet leak detectors as the pumps are more expensive.

For more information on the entire leak detection process, see the Technical Info section where information is available detailing all aspects and applications for helium leak detectors.

Common applications for vacuum helium leak detection include:

• Vacuum Furnaces
• Semiconductor Tools
• Vacuum Coating Systems
• Space Simulation Chambers
• Leak Detection Chambers

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