Helium Mass Spectrometer Leak Rate Calculator

Convert leak rates across standards (mbar·L/s, Pa·m³/s, atm·cc/s), calculate sniffing accumulation, and convert between tracer gases per ASTM E498/E499.

Measured Leak Rate & Units

Measured Leak Rate Value:

Input Rate Unit:

Helium Tracer Concentration (%): 100% pure He or forming gas (5% He / 95% N₂)

Sniffing Accumulation Vol (L): Bagging or hood volume

Converted Leak Rates & Concentration

Standard Rate (mbar·L/s):

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Standard Rate (atm·cc/s):

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SI Rate (Pa·m³/s):

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Equivalent Air Leak Rate:

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Sniffing Build-Up in 10 min (ppm He):

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Frequently Asked Questions

What is the natural atmospheric background of Helium?

Ambient air contains approximately 5.24 ppm of Helium. Sniffing probes detect leaks by measuring concentration rises above this natural background baseline.

Why convert Helium leak rates to equivalent Air leak rates?

Helium (molecular weight 4 g/mol) diffuses 2.69 times faster through micro-channels in the molecular flow regime than air (28.97 g/mol), per Graham law: Q_air = Q_He · √(M_He / M_air).

What are standard leak rate acceptance criteria in industry?

Hermetic semiconductor packages: < 10⁻⁸ mbar·L/s; High vacuum systems: < 10⁻⁹ mbar·L/s; Ultra-high vacuum (UHV) and particle accelerators: < 10⁻¹⁰ to 10⁻¹¹ mbar·L/s.