FUKUDA

MEASUREMENT PRINCIPLE OF HELIUM LEAK TEST

A leak is detected through the helium leak test by charging helium gas to the tested work and passing the leaked gas through the mass analyzer tube to detect helium only.
Tracer Gas
Helium is used for the gas to be charged in the tested work. For concentration, helium gas of 100% as well as dilute gas can be used. In addition, the used helium gas can be collected and used again since helium gas is costly.
Principle of Detection
The leaked helium gas is ionized by the electron beam from the filament within the ion chamber of the analyzing tube. The ions are accelerated and move out through a slit and then pass through the magnetic field generated by the analyzer. Since the circular trajectories of the ions depend on their mass, the collector can catch only the helium ions and detect helium.
[Figure]Principle of Helium Leak Test
Applicable product

MEASUREMENT METHOD OF HELIUM LEAK TEST

The bell jar method is widely applied for the helium leak test. In the bell jar method, helium gas is charged by depressurizing the work so that the concentration of helium gas is not decreased by atmospheric pressure. Gas in the chamber is sucked to detect leaked helium and judged by the detector. Helium inside the work is discharged and cleaned with nitrogen gas.

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