Varian 938-41 Helium Leak Detector with Turbo Pump Working See Video

Technical Notes:

Varian 938-41 Helium Leak Detector, tested and functional. The unit uses a turbo pump and requires an external roughing pump; an Edwards RV5, recently verified to reach an ultimate pressure of 3 microns, was used for testing. With this pump, the inlet port easily reaches below 10 microns. The unit’s built-in vacuum gauge was checked against an external micron gauge and reads slightly behind the actual pressure. All knobs, buttons, and switches operate as intended. The turbo pump runs normally and brings the spectrometer tube below 0.1 micron. We completed a calibration with a 5.7 × 10⁻⁸ atm·cc/sec standard leak, and the unit has previously been used to test a part with a leak rate on the order of 10⁻¹⁰ atm·cc/sec without issue. See video for a demonstration.

Please note that this unit was manufactured in 1998. Although all key functions work, the elastomer seals and O-rings are likely aged and may raise the background signal, which matters given the instrument’s sensitivity. Replacing them is recommended for best low-range performance.

Model Description:

The Varian 938-41 is a turbo-pumped helium leak detector built for precision vacuum integrity testing, widely used in R&D labs, manufacturing QA, and vacuum system diagnostics across semiconductor, aerospace, and industrial applications. Confirmed working condition, with operation demonstrated on video.

Highlights

• Integrated turbomolecular pump for fast, reliable high-vacuum leak detection
• Suitable for leak testing sealed components, chambers, and vacuum systems
• Proven functional performance, verified via video demonstration
• Trusted Varian engineering for consistent, repeatable sensitivity in lab and production environments