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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·m 3 ·s −1.
A tracer-gas leak testing method is a nondestructive testing method that detects gas leaks. A variety of methods with different sensitivities exist. Tracer-gas leak testing is used in the petrochemical industry, the automotive industry, the construction industry [1] and in the manufacture of semiconductors, among other uses.
The helium leak test uses helium (the lightest inert gas) as a tracer gas and detects it in concentrations as small as one part in 10 million. The helium is selected primarily because it penetrates small leaks readily, is inert and will not react with the test piece while having a naturally low quantity in air making detection less complicated.
A leak appearing within an analytic region (a rule added to the camera) is immediately analyzed for its attributes, including thermal temperature, size, and behaviour (e.g. spraying, pooling, spilling). When a leak is determined to be valid based on set parameters, an alarm notification with leak video is generated and sent to a monitoring station.
During the final hour of their approach to the space station, Starliner’s crew began to manually pilot the spacecraft in a planned test of Starliner’s manual flight control capability.
A major advantage is that this gas is noncombustible. But the use of helium has some disadvantages, too: The diffusion issue shared with hydrogen (though, as helium's molecular radius (138 pm) is smaller, it diffuses through more materials than hydrogen [4]). Helium is expensive. Although abundant in the universe, helium is very scarce on Earth.
If analyzing for hydrogen, the peak will appear as negative when helium is used as the reference gas. This problem can be avoided if another reference gas is used, for example argon or nitrogen , although this will significantly reduce the detector's sensitivity towards any compounds other than hydrogen.
The helium leak was a setback for SpaceX, which has been ferrying NASA astronauts to and from the International Space Station since 2020. SpaceX carried its first private citizens into orbit in ...