Why is helium used in mass spectrometry?

Helium is used as a tracer because it penetrates small leaks rapidly. Helium also has the properties of being non-toxic, chemically inert and present in the atmosphere only in minute quantities (5 ppm). Typically a helium leak detector will be used to measure leaks in the range of 10−5 to 10−12 Pa·m3·s−1.

How do you test for helium leak?

A spray gun is used to spray a fine jet of helium search gas at areas suspected of leaking. Again the helium enters through leaks present at the evacuated test object and the detector connected to it. The detector indicates if a leak is present at the area the helium search gas is exposed to.

Why is helium used as a tracer gas?

In contrast to hydrogen however, helium meets all requirements for a tracer gas in that it is safe for both humans and the environment, non-flammable, not normally present in the air (making it is easy to detect and avoid contamination) and is distinct from other gases (meaning it is measurable when testing for leaks).

What is helium leak detector?

A helium leak detector, also known as a Mass Spectrometer Leak Detector (MSLD), is used to locate and measure the size of leaks into or out of a system or containing device. The tracer gas, helium, is introduced to a test part that is connected to the leak detector.

What is mass spectrometer leak detector?

The Mass Spectrometer Leak Detector is a complete system for localization and measuring of leaks inside or outside of a product. This method uses so called tracer gas – helium, which is used to fill up the product connected to the detector.

How does a helium mass spectrometer work?

The principle of leak detector is based on a sector field mass spectrometer. Analyzed entry gasses (in this case Helium) are ionized in vacuum. Ions of helium are accelerated using added voltage and further separated in the magnetic field. The ion current is, using a special detector, turned into an electric current.

What is helium leak rate?

The basis of leak rate calculations are: the diameter of the leak is circular; and the leak channel is equivalent to the thickness of the material that the leak “passes” through. Leak rate = gas amount/time = pressure x volume/time, and is measured in mbar*l/s or equivalent units.

What gas is used for leak detection?

Helium
Helium is the most commonly used tracer gas in leak detection. It is non-flammable, non-destructive, non-toxic, inert, and only has trace presence in our atmosphere.

Is used as tracer gas for leak detection?

Tracer gas leak detection with helium and hydrogen.

What is helium used for?

Helium is used as an inert-gas atmosphere for welding metals such as aluminum; in rocket propulsion (to pressurize fuel tanks, especially those for liquid hydrogen, because only helium is still a gas at liquid-hydrogen temperature); in meteorology (as a lifting gas for instrument-carrying balloons); in cryogenics (as a …

What is STD CC SEC?

cc/sec) Std.cc/sec= One cubic centimeter of gas flow per second at 14.7 psi of pressure and a temperature of 77o. Std cc/sec.

How does helium leak detector work?

Helium is applied to the the potential leak site using a spray probe. If a leak exists, helium enters the system and quickly diffuses through it. The leak detector should respond within seconds. Pressure systems can be charged with helium or a mixture of helium and nitrogen.