A device that delivers a known, stable leak rate, typically a helium reservoir behind a permeation membrane or a capillary or crimped-tube restriction, certified at a reference temperature. Permeation types cover about 10⁻¹⁰ to 10⁻⁷ mbar·L/s and drift by a few percent per kelvin, so the reading is corrected for temperature. Techs check the detector against it at the start of a shift and after any service.
Calibrated leak reads 3.1E-8 against a cert of 3.0E-8, detector's good, go ahead and test.
Also heard as
- standard leak
- reference leak
- cal leak
Related terms
Helium leak detector
Mass spectrometer tuned to helium that finds and measures leaks by detecting helium drawn into the system.
Leak rate
Quantity of gas entering a vacuum system through a leak per unit time, usually in mbar·L/s.
Counterflow
Leak detector layout in which helium travels backward through a turbo pump's exhaust to reach the mass spectrometer.