The gas flow through a leak expressed as a throughput, in mbar·L/s, Pa·m³/s, Torr·L/s or atm·cc/s, all of them pressure times volume per time. Useful conversions: 1 Pa·m³/s is 10 mbar·L/s, 1 Torr·L/s is about 1.33 mbar·L/s and 1 atm·cc/s is about 1.01 mbar·L/s. For scale, 10⁻⁶ mbar·L/s lets in roughly 1 cm³ of air at atmospheric pressure every 12 days, and good UHV systems are specified below 10⁻¹⁰ mbar·L/s.
Leak rate on the new spool weld came in at 2E-10 mbar litres per second, well under the 1E-9 spec.
Also heard as
- leakage rate
Related terms
Helium leak detector
Mass spectrometer tuned to helium that finds and measures leaks by detecting helium drawn into the system.
Calibrated leak
Reference leak with a certified helium flow, used to calibrate and check a leak detector's readings.
Rate of rise
Test that isolates a pumped chamber and tracks how fast the pressure climbs, to estimate leaks and outgassing.
Gross leak
Leak big enough to stop a system pumping down properly, or to be found without sensitive instruments.
sccm
Standard cubic centimetres per minute: a mass flow unit for process gases, referred to 0 °C and 1 atm.